Not many people predicted they would meet again in the Eastern Conference Finals. Not after Boston lost Kyrie Irving and Gordon Hayward to injury. Not after Cleveland turned over its roster at the Trade Deadline. Not after both were pushed to seven games in the First Round and met seemingly formidable opponents in the Eastern Conference Semi-Finals.
But here they are again — the Cleveland Cavaliers vs the Boston Celtics for a berth in the NBA Finals. Cleveland becomes just the third team in NBA history to face the same playoff matchups in the first three rounds in consecutive seasons. But much has changed since the Cavs beat the Celtics last season.
The Chess Match
Throughout these playoffs, the Cavaliers have committed to starting Kevin Love at Center in all but Game 7 against the Indiana Pacers. While Boston has committed to a group of Terry Rozier, Jayson Tatum, Al Horford and Jaylen Brown (Marcus Smart with Brown not healthy), Brad Stevens juggled the fifth spot in the series against the Milwaukee Bucks.
Stevens started rookie Semi Ojeleye to deal with Giannis Antetokounmpo, sending starting Center Aron Baynes to the bench.
The question in this series is whether the newly-minted three-point threat Baynes (9-19 in these Playoffs after going just 4-29 in his career previously) continues to start and, if not, who rounds out the lineup in his place?
Boston has a few different directions it could go with Baynes on the bench. The Celtics could again turn to Ojeleye, Smart or insert Marcus Morris to draw the assignment against LeBron James.
A few things of note on Baynes. In the Playoffs, the Celtics have rebounded 28 percent of their misses with him on the floor and just 16 percent when he sits. But Boston has played its fastest when he sits (97.08 possession pace) and its slowest when he plays (93.16 possession pace). Boston has a -5.5 Net Rating with Baynes on and a team-best +5.6 Net Rating when he sits.
From an opposing perspective, the Cavaliers may want to turn to Tristan Thompson to neutralize Al Horford’s successful play so far in the postseason. Horford is averaging 17 points and 8.7 rebounds per game in the Playoffs on a 65.3 true shooting percentage.
But he has historically struggled against Thompson — especially on the glass. The Celtics had just a 92 oRTG when the duo shared the floor in the regular season. But it is important to keep in mind that Thompson starting likely means Baynes would matchup with him defensively as opposed to Horford, perhaps neutralizing some of his impact on the offensive glass.
If Thompson does start, Larry Nance Jr. may also return to Cleveland’s rotation off the bench. Nance had eight points and three rebounds in six minutes of Game 4 garbage time vs Toronto and appeared springier than when we last saw him against Indiana:
How Stevens and Tyronn Lue move their pieces around the chessboard will be a fascinating subplot of the series.
Boston on Offense
With Kyrie Irving out for the rest of the season, Boston has altered its offense in a number of meaningful ways.
The Celtics most frequent offensive initiator is its “Chest” series, which is often run for Jayson Tatum.
The series grants Boston optionality in how it will proceed once the initial action occurs. But every action begins the same way — two players in a stack in the middle of the floor at the free throw line and two shooters spaced to the corners. The player at the top of the stack (usually Horford) sets a screen for the player behind him (usually Tatum).
The first option off “Chest” is an isolation for the player coming off the screen.
Here, Horford goes to set a pin down for Rozier in the opposite corner, leaving Tatum to Isolate on the left wing.
The second option is Boston’s most common off the “Chest” action.
Horford flows with Tatum into a ball screen on the left wing, allowing Tatum to get to his preferred right hand.
The third option is a flare for the bottom player in the stack combined with an immediate step-up screen from the top player for the ball-handler.
In the case of an overplay, Boston can also counter the action by having the bottom player flare to the right wing rather than using the initial downscreen.
With Covington shading the right wing, Tatum flares to the left wing and Morris follows him to set a ball screen. Note that Tatum refuses the screen to once again get to his preferred right hand.
The spacing in the action is incredibly important as it forces most defenses to play the Tatum-Horford ball screen two-on-two. If a defense switches, this leaves Horford with a mismatch in the post. If they drop, Horford can pop for three. Worry about Horford and Tatum can get by you in a straight line drive to the rim.
For more on how Boston used “Chest” against Philadelphia, check out Jeff Siegel’s piece here.
The other main offensive engine for the Celtics is a Stagger series designed to either get looks for shooters or flow into a ball screen action.
The normal action looks like Toronto’s Double Drag series, where DeMar DeRozan would come left to right off a staggered pindown. Tatum does the same here:
But when the opposition is setting up to defend the stagger (as Ilyasova is here), Boston can quickly counter by turning it into a simple wide pindown. This look frees Marcus Morris for three before Ilyasova can react:
Finally, when there is no advantage gained off the stagger, Boston can turn this into a pitch ball screen action.
Brown is facing a stacked defense so he pitches it to Rozier who then dribbles off a ball screen from Horford — who was the second screener on the initial stagger action.
Lacking offensive stars Gordon Hayward and Kyrie Irving, Boston has prioritized hunting mismatches offensively in the Playoffs.
The Celtics have run Post Ups on 12 percent of their possessions (fifth most frequent) and Isolations on 14 percent of their possessions (sixth most frequent) in the Playoffs. This has come to the detriment of pick and roll offense — which only accounts for 23 percent of their possessions (fourth least frequent).
But an increase in frequency has only resulted in an increase in efficiency out of the post. Boston is scoring the sixth most points per play (ppp) on post-ups in the Playoffs, compared to the 14th most ppp on both Isolations and pick-and-rolls.
The largest beneficiary in the increased Isolation play has been rookie Jayson Tatum, who spent much of the Philadelphia series hunting matchups against JJ Redick and Marco Belinelli.
Tatum has only scored 0.75 ppp (29th percentile) in Isolation and has thrown six competitive passes on 50 total Isolation plays. Morris (0.9 ppp) has been Boston’s most effective Isolation scorer, but ranks only in the 51st percentile in the Playoffs.
The same story, however, is not true for Post Up possessions. Al Horford has been a beast in the Post all Playoffs, scoring an NBA-leading 1.18 ppp. He has especially brutalized mismatches, shooting 12-18 against Antetokounmpo and Dario Saric.
Horford loves to get to his right shoulder in the Post (47 percent of the time — compared to only 18 percent over his left) and will do so even when he gains an advantage going right.
He has also been a strong distributor when the defense collapses and Boston has scored 1.36 ppp on these plays as a result.
His success down low has led to Horford increasing his proportion of Post Ups from 34 percent of his plays in the regular season to 44 percent of his plays in the Playoffs.
Tatum and Smart have also seen their proportion of Post Ups increase — largely as a function of the matchup-hunting style Boston has employed.
Running off the Line
No team has been more dependent on three-point shooting than the post-Irving injury Celtics.
Since Irving went down, they are shooting 40.4 percent from behind the arc in wins and only 33.6 percent from downtown in losses. They have been able to get attempts up at the same rate in these games (~30 per game) and have taken 33.4 percent of their shots from deep in the Playoffs (4th most).
Boston shot 37.3 percent from three in its series win over the Sixers and is now shooting 36 percent overall from behind the arc in the Playoffs.
But digging into the numbers paints a more complete picture.
The Celtics are shooting 43 percent from three on 11.8 wide open attempts per game, 34 percent on 13.7 open attempts per game and just 26 percent on 5.2 tightly guarded attempts per game. They have a 48.2 effective field goal percentage on guarded Catch and Shoot attempts and a 65 eFG percentage on unguarded Catch and Shoot attempts.
Overall, Boston has a 57.3 eFG percentage on Catch and Shoot but just a 36.1 eFG percentage on off the dribble jumpers. This is highlighted by Rozier — who has shot 46.7 percent on Catch and Shoot jumpers but only 26.5 percent off the bounce.
They don’t have a ton of shooters comfortable with getting shots off in a tight window. Cleveland should be focused on closing out to shooters’ feet and making them put the ball on the deck. This can take away three point attempts for a guy unwilling to shoot it off the bounce like Horford.
When Boston’s players attack closeouts, they tend to get a bit pass-happy. The Celtics rank third in the Playoffs in passes per game (309) but only ninth in Assists per game (21.2) and 10th in Potential Assists per game (38.2).
This has led to them playing late in the shot clock more often than any other team in these Playoffs. Boston has taken 28 percent of its shots with seven seconds or less remaining on the shot clock. But the Celtics remain composed in these situations and have shot 46 percent on shots with seven seconds or less on the clock (but much worse than the 59 percent they have shot on attempts in six seconds or less).
As noted above, the largest facet of Boston’s offensive gameplan against Philadelphia was attacking weak defenders. This meant seeking out players like Redick and Belinelli and being comfortable compromising the offense in favor of these matchups.
In that series, Boston had a 119 offensive rating on the 129 possessions Redick, Belinelli or TJ McConnell guarded Tatum.
The rookie had 37 points on 13-23 shooting on these possessions.
This matchup even made Marcus Smart post-ups a viable option — even though Smart scored just 0.75 ppp on post-ups in the regular season.
I fully expect the Celtics to do the same to Kyle Korver in this series. Using prior series as data points, it is hard to imagine LeBron James guarding either Tatum or Brown. Instead, James will likely be in a free safety position off whichever player of the Smart/Morris/Ojeleye trio ends up starting for Boston.
This will leave Korver on either Brown or Tatum — who is averaging 23 points on 51 percent shooting over his last seven games. Given the Celtics’ propensity to hunt matchups with Tatum and Brown’s ongoing hamstring troubles, Korver appears likely to start on Brown.
Brown was used much more as a spot up shooter as opposed to an offensive initiator in the Sixers series — dropping his field goal attempts by 1.8 per 36 minutes. More telling was his drop in drives per game from 7.3 to 4.3.
The Cavaliers should look to make Brown prove he can take advantage of Korver in Isolation situations (he has only five plays of this nature so far these Playoffs). Expect Jeff Green to draw some minutes on Tatum if the rookie starts cooking.
Cavaliers on Offense
After struggling offensively against Indiana, the Cavaliers came alive to the tune of a 121 oRTG en route to dismantling the Toronto Raptors in four games. Cleveland now ranks 3rd in Playoff oRTG (113) and tied for 1st with Houston in half court oRTG (100.3).
One main feature of Cleveland’s offensive success against the Raptors was the return of George Hill from his back injury. In 296 minutes that Hill and Kevin Love have shared the floor this season, the Cavaliers have a 122.1 oRTG.
In addition, Cleveland’s new starting five of Hill, Smith, Korver, James and Love has posted a blistering 125.5 oRTG in 110 minutes. The group has a 67.8 True Shooting percentage in those minutes.
Who Guards LeBron James?
As with any series that involves the Cleveland Cavaliers, this is the most important question for the opposition.
For Boston this season, the task has fallen mainly on the shoulders of Brown (57 possessions) and Morris (55 possessions).
Brown has been the better of the two, “holding” James to 19 points on 8-15 shooting, four assists and three turnovers. Despite what may have been true in 2016, James has torched Morris for 24 points on 8-16 shooting, 10 assists and just one turnover.
In the Playoffs, James has averaged 34.3 points, 9.3 rebounds and nine assists per game on 55.3 percent shooting. He has been efficient from, well, everywhere.
The Celtics faced Antetokounmpo and Joel Embiid already in these playoffs — each of whom has been efficient operating out of the post.
When the Bucks and Sixers did not play with requisite off-ball movement on these post touches, the Celtics were able to maintain a defensive shell while guarding the post 1-on-1.
But that shell felt susceptible to collapse at times when the opposing team began cutting off the ball.
Milwaukee runs an off-ball stagger that is similar to Cleveland’s post up actions (though for worse shooters) here. Watch Al Horford help off the screener onto the post, allowing Parker to slip free to the bucket. A three-point shooter in his position makes this help even harder.
The Cavs may also find success having a point guard set a ball screen for James, knowing the Celtics are unlikely to switch the action.
The Cavs found success using guard screens for James against Toronto against show and recover coverage.
Here, Korver pops for three but the Cavs can also use this action to attack the basket with a spaced floor.
Ultimately, expect Boston to try to contain James 1 on 1 without bringing much help when he has the ball. He shot 17-20 at the rim (85 percent) against the Celtics in the regular season and demonstrated a strong ability to get downhill in semi-transition.
But Boston — like Toronto and Indiana — will likely feel that limiting his assists is the best way to stop the Cavs. From their previous series’, it appears as if the Celtics will have better gameplan discipline in their execution.
The Korver-Love Dance
Kyle Korver leads all postseason players in off screen efficiency, scoring 1.78 points per play on these actions. It will be imperative for Boston to not allow him to get going on these wide pindowns.
But as the great Zach Lowe noted, the Korver-Love ballet presents intricate challenges for an opposing defense. The Cavaliers used the Raptors switching this action to get Love going in the post, resurrecting him from the depths of the Pacers series and putting the offense back in elite company.
Against JJ Redick in the last series, Boston was often in lock and trail coverage on wide pindowns (though they occasionally threw in some top-locking and some blitzing on the catch).
While this is the same coverage they used against Korver in the regular season, Joel Embiid is not Kevin Love. The Sixers did run an interchange with Redick and Ersan Ilyasova to start Overtime of Game 3, but Boston switched the action in time:
If Smart is on Korver, the Celtics may switch the action and allow him to use his strength against Love in the post. But put a smaller player in Smart’s place and that strategy becomes more difficult. Love can punish these guys in the post. Blitz and Korver is one of the most adept at making pocket passes to roll men.
How Boston handles this action will be a fascinating subplot of the series.
Other Offensive Tidbits
Boston’s halfcourt defense has been below average so far in the Playoffs. They have allowed 95.9 points per halfcourt possession which ranks 11th overall and worst of any remaining Playoff team.
A large portion of this is that they are allowing 1.17 ppp on Spot Ups, despite surrendering just 34.6 percent shooting from downtown. The Sixers shot just 31 percent from three against Boston, including an abysmal 25.5 percent on open threes.
As a contrast, Boston succeeded against both Philadelphia and Milwaukee largely due to its excellent transition defense (the best in the NBA in the regular season). But this figures to be less impactful against a Cleveland team that has played the slowest pace in the Playoffs (93.19 possessions per game) and has only run on 13.7 percent of possessions.
Cleveland turned it over on just 8.2 percent of possessions against the Raptors, including just three total turnovers in Game 2. The Cavs continue to take care of the basketball when George Hill plays, preventing opponents from running out in transition and getting easy buckets.
Boston’s defense is more reliant on contesting shots than forcing turnovers. They ranked 12th in turnovers forced in the regular season and have only forced turnovers on 13.9 percent of possessions in the Playoffs.
The Celtics struggled to contain Antetokounmpo at the rim, allowing him to shoot 74 percent on over 8 restricted area attempts per game. They have surrendered 67.3 percent shooting at the rim overall in the Playoffs and now face a Cleveland team that has converted over 70 percent of its attempts in the restricted area in the postseason.
After struggling mightily against the Pacers on corner threes (26.7 percent), Cleveland shot a blistering 60 percent from the corners against Toronto. They are attempting 11 percent of their shots from the corners in the Playoffs — tied for first with Houston.
This will be another game within the game, as Boston’s defense allowed the fifth fewest corner three point attempts in the regular season. They have allowed 6.5 percent of shots from the corners so far in the Playoffs but have faced teams that do not generate many looks from the corners in Milwaukee (12th most) and Philadelphia (29th most).
This Celtics team is by no means perfect but they do present some matchup troubles for Cleveland defensively. They are going to attack Korver and Love as they continue to play mismatch basketball to generate good looks. They are also likely to push the pace a bit more than they usually do in transition — especially off live rebounds.
Cleveland will counter by likely blitzing Rozier, who was a bit shaky handling two defenders when the Sixers sprung some surprise traps.
Boston will trust Horford to make the right pass if he gets the ball in the short roll and Cleveland will try to deny that entry. The Celtics will unleash Tatum against Korver whenever they can.
But, as most series do against Cleveland, this will come down to offense. And when push comes to shove, this iteration of Boston does not have the offensive firepower to hang with the Cavs.
They have a multitude of players to throw at James but none are Andre Iguodala or Kawhi Leonard-level stoppers. They can switch the Korver-Love actions, but Cleveland will feel comfortable with Love in the post. Cleveland can counter with Hill-Love pick and roll and dare Boston to switch Rozier onto Love.
Brad Stevens will challenge Cleveland with his gameplan, but there is nothing LeBron James has not seen before. Right now, he is the single biggest advantage in these Playoffs. Defense starts with slowing him down. Nobody can stop him, not even in Year 15.
When it’s all said and done, James will return to his 8th consecutive NBA Finals and Cleveland will await the winner of what appears to be a Houston-Golden State clash for the ages.
Prediction: Cavs in 5