The Spurs didn’t make any huge center additions but have the possibility to play big, small, and anything in between. While there are a lot of new faces at guard and some intriguing storylines to follow at the forward positions, the Spurs’ center rotation doesn’t really feature any new or exciting names. Jakob Poeltl is still around to start while Zach Collins will be his main backup, just like last year. Providing depth behind them will be Gorgui Dieng, returning to San Antonio after a year in Atlanta. The average age of that group is 27 years old, which is…