San Antonio Spurs: Finding the analytically perfect rotation

Analysis

No matter how good something looks, though, we still have to see if it works. Most of these categories are self-explanatory, but “real minutes” are how many minutes that lineup has actually played together this season.

The first picture is the raw data as initially calculated as specified. However, four of the eight lineups had less than 10 minutes played together, so I redid the calculations in the second picture.

More specifically, I calculated each player’s per 48 minutes plus/minus for the year, and averaged the plus/minus of the five players in a particular lineup. It’s an imperfect approximation, but a necessary one. The results in the second one are much more reasonable.

You may notice that the total is negative, and what that means is that if the San Antonio Spurs were to implement this rotation, they would be expected to lose by 0.377 points. Currently, they actually outscore opponents by roughly 1.3 points a game, so it wouldn’t make perfect sense for them to implement this.

However, just because they shouldn’t use this specific rotation doesn’t mean there aren’t things we can learn from it.

Of the four lineups with the Gay-Cunningham-Aldridge frontcourt (which is the frontcourt that currently starts for the San Antonio Spurs), only one is (barely) positive, and two of the three negative ones are the two most negative out of all of the lineups. The lineup that includes those three and DeRozan is the worst out of all of them. According to NBA.com, that trio has a net rating of -5.1 when they play together.

Surprisingly, the best lineup isn’t that different from the worst. Both include Mills, DeRozan, Gay and Aldridge (the teams four best shot creators), but the more effective lineup includes Bryn Forbes instead of Dante Cunningham.

There’s a lot of ways to interpret that information. Perhaps it says that having a volume 3-point shooter is especially critical next to lineups of more ball-dominant players, but perhaps it just means DeRozan and Gay are worse at the 2 and 3 than they are at the 3 and 4, respectively.

I actually made that lineup almost by accident because of other restrictions; I didn’t intend to play Gay at the 4 at all, but now I’m rethinking that. More Gay at the 4 at the expense of Cunningham might be a bad idea, but that means more minutes from one of the guards as a result.

Mills and Poeltl seem to be two of the more important players in the San Antonio Spurs’ rotation, as their lineups seem to do better than most of the others. For example, Mills is in all three positive lineups. Unsurprisingly, they have two of the best plus/minus stats on the whole team.

Technically, this experiment wasn’t a complete success. This rotation isn’t any better than what Pop comes up with on a given night, at least so far. However, some important lessons were learned: Gay should play more at the 4, and without Cunningham. Forbes is an important member of the team, and maybe Mills, Belinelli or Derrick White needs more minutes. Hopefully, some of these changes will be implemented moving forward.