Gas left in the tank
The first and most obvious pro is that he should help the team compete this year. However, that’s not a given fact. He’s getting up there in years (Tim Duncan retired when he was “only” 39, compared to Ginobili’s 41), and it’s hard to know what the Spurs will get from him.
Since he started coming off the bench full-time in the 2011-12 season, Ginobili’s minutes have steadily declined from 23.3 per game that year to 18.7 per game in 2016-17. However, he actually played 20.0 minutes per game last year, and performed as well as any Spur in the playoffs, so it’s unclear if he’ll drop off.
Ginobili’s a good shooter, at 36.9 percent from deep in his career. However, he’s not some spot-up sniper that can stand in a corner and play forever because his game isn’t tied to athleticism. Clearly, he has to get worse at some point.
When that will actually be is anyone’s guess, though. Ginobili is very much like the San Antonio Spurs themselves: every year, they get written off as too old/slow/untalented/boring, and then they end up surprising everyone and being great again.
Ginobili being good or bad as a player brings up separate issues anyway. If he’s still good, while that helps the Spurs this year, it may not be great for their long-term development. Veterans Patty Mills, Marco Belinelli and DeMar DeRozan all figure to get a lot of minutes this year. Youngsters Dejounte Murray, Derrick White, and Lonnie Walker IV are also contenders for playing time. Even Bryn Forbes is there to throw his name in the ring.
If Ginobili is back and still playing 20 minutes a game, he and Mills will hoard all the backup minutes for positions 1-3 (assuming the starters are Murray, Belinelli and DeRozan). In other words, his presence would likely push White, Walker and Forbes out of the rotation entirely, barring injuries.
Again, that would be better for the Spurs this year. They’ll obviously be trying to make the playoffs, and getting quality contributions from Ginobili would only help.
But similarly to how Tony Parker’s injury in the 2017 NBA Playoffs helped Murray’s development, the absence of Ginobili could help White, Walker and Forbes. For a team unlikely to make the Finals this year, a year of development for those three might be more important than getting the 4-seed instead of the 6-seed.