When Mo Williams last played for the Cleveland Cavaliers, he made an All-Star team. For a stretch, he was the second best player on some Cavs teams that, without LeBron, were dreadful.
This time around, Williams himself is a different player. His role will be different too.
In signing a two-year deal worth $4.3 million to return to Cleveland, Williams joins a Cavs team that made the Finals last year and has opened up a clear title window. LeBron is the constant - it all starts and ends with the King - but this Cavs team has legit star power beyond LeBron. In Kevin Love and Kyrie Irving, the Cavs have two top-15 players who are on the right side of 30. In theory, what Williams does compliments both.
Williams' role is likely going to be as a hybrid backup guard. His best NBA skill is his shooting and that walks in line with what the Cavs do. He can spell Irving at point guard or he can slide next to Irving and play as an off guard against certain teams. He also gives the Cavs another player who can handle the ball and, in small doses, do some creating for others. Williams might not play a ton, as Irving is going to play more than 30 minutes a night and Williams will have to share minutes with Iman Shumpert, J.R. Smith and Matthew Dellavedova. Of course, this assumes that the Cavs will re-sign both Smith and Dellavedova.
The issue with Williams is that he's regressed since leaving Cleveland. He's had some nice seasons and scored 52 points in a game last year, but he's not particularly efficient. Williams two full years in Cleveland were his two best years. In 2008-09 - the year he made his lone All-Star appearance - Williams had an eFG% of 54.8 shot 43.9 percent of his threes while playing 35 minutes a night. The next year, Williams posted slightly lower numbers while playing roughly the same minutes.
Williams was 26 during his best individual season. He's 32 now and his game hasn't aged in a way that makes him sure bet to be effective in a smaller role. His eFG% is lower now and his 3-point percentage has dropped in every season since he left Cleveland. He's also seen a small uptick in his turnovers per game, although he was playing for some bad teams. In Cleveland, you'd have to hope he tightens up his game a little bit and you probably don't want to pair him with Smith at any point.
His shot chart from last year shows more of the same:
The most concerning part of Williams' aging is that he's a sieve on defense. He's never been a particularly good defender, but he's gotten worse as he's aged. There's been a loss in quickness and aside from his 27 games with the Hornets, his personal defensive rating has been well north of 100 for years. Depending on who the Cavs are playing, David Blatt will need to be careful about playing Williams extended minutes. As a general rule, he's probably best used alongside Shumpert when possible so you can attempt to hide him on the opposing team's weakest offensive threat.
You'd have to think, or at least hope, that Williams will dial back his gunner mentality with the Cavs. There isn't a need for Williams to be a high usage player and for him to be as effective as possible, he'll have to take smart shots, put in effort on defense and play off of everyone else. In addition, he'll need to be a veteran voice on a team that still needs them. Williams has a history of being a good locker room guy - he was loved in Cleveland before and everywhere he's been sense - and that should continue here were he'll be a different, if not better, veteran voice for Irving than Jarrett Jack.
If Williams does those things and can settle into a small, but comfortable role, there's no reason to think he won't be good bargain pickup for the Cavs. But it's an if nonetheless.