The Celtics held a rare morning shootaround at the AT&T Center in San Antonio this morning in advance of tonight's showdown with the Spurs.

While this seems to go against the team's usual practice of not holding shootarounds on game days, Celtics coach Doc Rivers explained they've modified the "Celtics Time" rules ever so slightly.

"One thing we decided is a new rule -- the 48-hour rule," said Rivers. "If we go 48 hours without touching a basketball, we'll have a [morning] shootaround. We didn't practice [Wednesday], so if you go game to no practice to a game the next night, it's too long without a ball. I think this is, what, our second [shootaround]? Otherwise, there's no shootarounds."

San Antonio media members were interested in the strategy since the Spurs and coach Gregg Popovich have installed a similar plan this season.

"We like it, it's been great," said Rivers. "Not only do we think guys are fresher, our practices are dramatically better. We practice at 1 or 2 o'clock. It's been amazing the difference. It's still early [in the season], but I think it'll keep getting better."

Summer of the Spurs: Rivers heaped praise on the Spurs, saying they "had the best summer of everybody," with the additions of Richard Jefferson, DeJuan Blair and Antonio McDyess. "Not only in terms of talent," said Rivers, "but also in terms of fit for the team."

No All-Star talk?: Asked if he thought center Kendrick Perkins was All-Star worthy, Rivers passed on offering his take. "I don't get into the All-Star conversation," said Rivers. "I let everybody else do that. Whatever. I hope all 12 of them make it. Just no coach."