At one point this coach thought it was a good idea not to play Nazr Mohammed and Rasho Nesterovic at the center position for a playoff run after the Spurs won 63 games with them. The biggest problem is that he likely doesn't think this front line he's created is broken. He's almost assuredly not aware of the years it's taken off Duncan's career. There are warm bodies out there that will do a better job at starting center than Matt Bonner. There are ten minutes of any game where you can put Blair and Bonner on the floor at the same time and do less damage than putting Bonner against an NBA starting center or power forward. The only thing Matt Bonner can do as a starting center is to statistically lower the average skill-level of starting NBA centers, which doesn't actually help the Spurs.
It constantly amazes me that otherwise knowledgable Spurs fans have just finally drunk the Koolaid of the coach's insanity because it's been part of our reality for five years.
Some realities of box-score management: Moving starters to your bench doesn't improve your bench. Moving bad players to the starting lineup just hides the damage the opposing starters do to the bad players. The plus minus stat has been a greater contributor to the Spurs' decline than knee tendonosis.
If the Spurs need a starting center, then suggest that the Spurs trade a draft pick for a center. If Matt Bonner can't play on the front line with Blair, then put in Leonard for ten of Bonner's fifteen minutes alongside him. The stupidest thing IN THE ENTIRE WORLD OF BASKETBALL is to say, "Hey this guy sucks, let's ing start him!"