Matt Cassel, the Kansas City quarterback who had an emergency appendectomy two days ago, will be listed as doubtful for this weekend's AFC West showdown game at San Diego.
Coach Todd Haley refused to say if Cassel would be out for Sunday's game.
"He's going to be listed as did not practice today and doubtful, and that's where I'll leave it," Haley said Friday.
Wearing sweat pants and a shirt while teammates worked out in pads, Cassel appeared to do nothing but light tosses during the short time the media was allowed to watch Friday's practice.
Cassel, having a Pro Bowl-type season, is a main reason the Chiefs (8-4) lead the Chargers by two games in the division. He's thrown 23 touchdown passes and a league-low four interceptions, managing the offense efficiently behind a running attack that leads the NFL.
Backup Brodie Croyle, who has started nine games for Kansas City since 2006 and lost every one, has worked with the first team all week and did again Friday.
Medical opinions as to how soon Cassel might return have varied. Doctors have said it would depend on how much pain and discomfort he feels following the operation, and how invasive the procedure was.
The Chiefs maintain a strict policy of not disclosing or discussing injuries. Haley hasn't even talked about hurting his own right leg during practice earlier in the year.
"I've been taught through all my years of coaching when you get into injuries and talk about injuries ... there may be some times that from a competitive standpoint it will hurt you," Haley said.
"Say you're talking about somebody who's got a specific injury and then you talk about it, and you've got some guys on the other side that don't want to see us succeed that are going to be going after body parts. People look for wraps and tapes and tape jobs and braces. They do that. That's part of the game. It's a physical game. I just don't want to ever put our guys in a position where you're putting them in a position of vulnerability."
Haley said he was unaware of remarks this week by Chargers linebacker Stephen Cooper, who said that if Cassel "does suit up, we are going to try to put him back on the bench if we have to."
Croyle has been plagued by injuries since coming to the Chiefs as a third-round pick out of Alabama in 2006 and has not started a regular-season game since the '09 opener.
While he's 0-9 as a starter, this is by far the best team he's had around him. Running backs Jamaal Charles and Thomas Jones could be both headed for 1,000-yard seasons. Dwayne Bowe had caught at least one touchdown pass in seven straight games until being stopped last week by Denver cornerback Champ Bailey.
"This is a very good team offense. We've got a lot of guys making a lot of plays," Croyle said. "If I get the opportunity, just go in there and continue to make the plays, and get the ball to the guys who have been making them."
Croyle is not as big as Cassel but has a stronger arm. Offensive coordinator Charlie Weis said the offense would not change if Croyle plays.
"The good thing is, with the way we do this, we always have the second guy, him get a limited number of reps during each week to make sure if he did have to go into the game, he's set and ready to go," Weis said. "All that's happened this week with Brodie is he's been fast-tracked. But I think mentally we couldn't be in a better situation because the kid's ready to play."