SAN DIEGO -- It appears unlikely that receiver Chris Chambers will play Sunday night when the Chargers host the New England Patriots, due to the sprained left ankle he suffered in Sunday's loss to Miami.

Chambers didn't practice at all this week and was listed as doubtful on Friday's injury report. He said he's not even sure he'll test the ankle in pregame warm-ups.

Chambers said he'll leave the decision up to team doctors.

"If I can make it this game, I'll make it," Chambers said. "If I can make it the next game (against Buffalo), I'll make it. It just depends. It's a day-to-day process."

Chambers said the ankle has improved steadily over the past few days and that he hasn't yet ruled out attempting to play.

He broke into a smile when asked if he was hoping to play, wanting to play or wishing he could play.

"All three of them," Chambers said. "Go have fun with that one."

Chargers coach Norv Turner said that reserve receivers Craig "Buster" Davis, Legedu Naanee and Malcom Floyd will all see action Sunday night. Turner said a decision on who starts -- whether it's Chambers or someone else -- will be made on Sunday.

What revenge?

Because the Chargers lost to the Patriots in last season's AFC Championship Game, several players have faced questions this week wondering if Sunday's tilt is a revenge game.

Running back LaDainian Tomlinson served up the best response in explaining how there's no way a mid-October victory over the team that kept you from the Super Bowl qualifies as revenge.

"For us, this is not a revenge game because nobody is going home if they lose the game," Tomlinson said. "It's just going to be another game and then next week you have another opponent. So it's not a revenge game at all."

What is clear is the importance of the matchup. The Chargers (2-3) are two games behind Denver in the AFC West and only five of the AFC's other 15 teams have won fewer games.

Losing to the Patriots and dropping to 2-4 would leave the Chargers facing a tough uphill challenge.

"It is a must-win game for us," Tomlinson said. "We need a win desperately. We can't afford to drop this one."

Veteran nose tackle Jamal Williams also senses the urgency.

"We know we have to win this game," Williams said. "I'm not going to say this is the most important of the season, but you're not going to just go out there and say 'Hey, we're going to go and lose this game.' Our approach is to go out and win every game."

Familiar face

New England's backup quarterback Sunday night is Kevin O'Connell, formerly of La Costa Canyon High and San Diego State.

O'Connell wasn't expected to take any snaps this season, but Tom Brady's season-ending knee injury changed his situation. O'Connell made a cameo appearance in the Patriots' 25-point loss to Miami and completed 3-of-4 passes.

"He's made good progress," Patriots coach Bill Belichick said. "Kevin has worked hard at it. He's a smart kid and he's picked things up pretty quickly -- things that are new to him -- so he's coming along."

Et cetera

OLB Jyles Tucker (hamstring) was listed as doubtful on Friday's injury report but said he will attempt to go through pregame warm-ups on Sunday to see if he has any chance of playing a limited role. "That's the plan right now, to try to go out there and see what we can do," Tucker said. "If I can go, then I'll go. If not, I'll sit down one more week and be ready for Buffalo." … The Chargers listed the following four players as probable for Sunday's game: CB Antonio Cromartie (hip), WR Vincent Jackson (knee), FB Mike Tolbert (ankle) and RB LaDainian Tomlinson (toe).

Contact staff writer Mike Sullivan at (760) 739-6645 or msullivan@nctimes.com.