James Posey replaced Antoine Walker in the Heat's starting lineup Saturday against the Bobcats, marking the first time since the 1998-99 season that Walker has come off the bench. For his career, Walker has started 678 games, and Saturday marked the 16th time he has been a reserve.

The Heat signed Walker with the idea that he would be the team's sixth-man extraordinaire, and after initially dodging the subject of coming off the bench in the preseason, Walker realized he could work as a reserve. But when Posey injured his right thumb, keeping him out for the first five games of the season, Walker was in the starting lineup as a small forward, averaging 15.3 points and 6.8 rebounds.

With Posey back, coach Stan Van Gundy said he wants to have a true small forward on the floor instead of forcing players out of position.

''It's a tough situation because even though he wasn't going to like it, he was ready to do it in the preseason,'' Van Gundy said. ``He knew it was coming. We had talked about it. He was ready to do it. And then Posey gets hurt, and he's starting six games and playing pretty well. Now I think it's a little bit harder to take. But he took it professionally, and he's still got to go out and produce.

``We'll see how it goes. Nothing is set in stone. I've changed lineups before. It just gives us a true three-man in there, a guy who can help chase guys off screens, which is a big thing playing these guys.''

Walker didn't seem thrilled with the idea when asked about it Saturday, but realistically, not many 29-year-olds who have averaged 20 points and nine rebounds in their career would.

''I never came off the bench before in my career, so I've got to get used to it,'' Walker said. ``I'll try to make the most of it. It's a new challenge. Just try to do it for the betterment of the team, and hopefully it is for the betterment of the team.''