“Thumb Fist” has Tyronn Lue and Brad Stevens battling back and forth

Very little is entirely unique in the NBA. Coaches and scouts aren’t just watching film to pick out what other teams do best; they’re looking for sets they can run with their own team with some tweaks depending on the personnel involved. Such is the case for Tyronn Lue and his staff, who were obviously watching the Portland Trail Blazers this season and have integrated Portland’s pet flare screen set into their offense.

There are a few different variations of the play, which the Trail Blazers call “Thumb Fist”, but the most common one the Cleveland Cavaliers run requires the big man setting the flare screen to step up into a ball screen:

George Hill comes off a down screen from the left corner and receives the pass from LeBron James to trigger the play. Meanwhile, J.R. Smith rotates over from the right to left side of the floor, mirroring Hill’s movement across the formation. Hill pitches the ball right back to James and continues on his route, curling around a flare screen from Tristan Thompson to the right corner. As soon as Hill clears him, Thompson sprints into a ball screen for James.

This set is effective because of what it does to Aron Baynes defensively — watch again how Baynes takes a small step back to ensure that he protects the rim in case Hill curls completely to the basket.

In doing so, he’s left slightly out of position for the James-Thompson pick-and-roll and James is able to rise up and hit the three over Marcus Morris.

Cleveland will also use this play to get Kevin Love a touch in the post, especially early in games when their plan is to get him heavily involved in the offense:

The play starts the same way, with Hill pitching back to James and going to the right corner, but instead of stepping into the ball screen, Thompson follows Hill to the corner for another down screen. James has two options here: he can wait for Hill to come off the down screen or he can fire it to Smith, who replaced Hill on the left side of the floor. James hits Smith, who throws it into Love for a post-up. With different personnel on the floor or a different matchup (particularly if the Cavaliers move on and face Houston in the NBA Finals), Love’s down screen for Smith would generate a switch and Love would have more of an advantage on that post-up than he does against Al Horford.

One aspect of the play to which Boston adjusted its effectiveness in Game 3 is that Cleveland never looks to throw the ball to Hill on that flare screen and therefore there’s no reason for the big man to sink back into the paint. Portland will do this every so often to keep the defense honest, though it obviously helps that they usually have Damian Lillard coming off that screen instead of Hill. Watch how Horford doesn’t react to the flare screen at all:

The Cavaliers score on this play, but the Boston defense is much more sound against this action than it was in Game 3. The rotations were almost perfect—Semi Ojeleye (James’ original defender), switched onto Thompson after the pocket pass before playing him off to Jayson Tatum and sprinting out to the corner to contest Smith’s three-pointer. Smith hits an impossible shot from that left corner, but Boston will live with him taking that kind of shot.

Lue adjusted back against what Boston was doing defensively in Game 4 but throwing a couple of small wrinkles in “Thumb Fist” for Game 5 — Hill was the original ball handler with Smith looping from left to right, and Thompson and Love switched spots in the initial action. Additionally, Love doesn’t step up to set the flare screen for Smith; Smith comes down to set a screen for Love to pop up to the perimeter for a three:

Boston is ready for this change and defends it well by switching Tatum onto Love as he came up to the right slot, but the additional weak-side movement by Smith opens up the entire right side of the floor for James and Love to work a two-man game. The Celtics are forced to bring the double onto Love in the post against Tatum and Thompson is able to sneak to the front of the rim and get fouled.

Where this game of cat-and-mouse goes from here is going to be an interesting subplot in Game 6. Cleveland ran less of “Thumb Fist” in Games 4 and 5 after running it a few times in Game 3, and it’s possible that they’ll nix it from their playbook altogether after Boston has shown that they’re able to adjust to the various continuations stemming from the original down screen and pitchback.

On the other hand, there is room for improvement in how they ran the play in Game 5 — James could get in on the screening action for Love, Love could first set a flex screen for James before coming off the down screen from Smith, or Love could come off the screen and immediately set a ball screen for Hill at the top, with the hopes that his defender is lagging behind the play and won’t be there immediately to switch on the pick-and-roll.