The Celtics were cruising along with a 20-point-plus lead for much of the second half of last night's 104-90 victory over Detroit at the FleetCenter, prompting Celtics coach Jim O'Brien to pull all of his starters early in the fourth quarter. That is, except Antoine Walker, who remained on the court until there was 7:15 left.

That appeared strange considering Walker's physical condition. Suffering from a severe case of tendinitis in his right knee, he had been regarded as questionable for the game. O'Brien was asked during his postgame press conference why he didn't replace his frontcourt star earlier in the blowout.

``He played in the fourth quarter because, as you saw down the stretch, I'm not comfortable in the NBA playing a team that's one of the best 3-point shooting teams in the league,'' said O'Brien. ``There's going to be sometime in my career here where Antoine or Paul (Pierce), in a (similar blowout) situation, is going to tweak an ankle, and you're all going to jump on my