The Celtics euphoric summer is officially over tonight, as the first pre-season game of the 08-09 season tips off at 7:00PM. The Celtics will be short-handed, as Sam Cassell will miss the game to be with his ailing grandfather. From the Globe:

Sam Cassell will miss the Celtics' opening preseason game against Philadelphia in Amherst Wednesday night to be with his grandfather, who sustained a heart attack, in Baltimore.

Cassell did not practice Tuesday, Gabe Pruitt filling the role of backup point guard and also performing at shooting guard.

"It's a good chance for me to play tomorrow," Pruitt said. "It's a chance to show what I can do.

"I've played the '1' and '2' my whole life, so this is nothing new to me."

Kendrick Perkins is also out (shoulder). And don't expect to see a whole lot of the PGA Tour, either, as coach Doc Rivers plans to severely limit the trio's playing time tonight. From the Globe:

Fair warning from Celtics coach Doc Rivers: It would be a good idea to get to tonight's preseason opener before the national anthem.

He wouldn't put a number on exactly how long he'd leave Ray Allen, Kevin Garnett, and Paul Pierce on the court against Philadelphia at the University of Massachusetts's Mullins Center, but the best way to keep count might be with a stopwatch.

"Put it like this," Rivers said. "Get there early would be my advice."

The way preseason works, the top two priorities conflict with each other. You want to get players on the court so they can develop a rhythm, but you also want to keep them healthy and ready to play 82 games.