One reason is he's knows how tall the task is to eliminate the Colts for the second consecutive year in the playoffs.
The other factor is he strained his groin in Sunday's win over the Broncos.
"A little sore (Monday), but that was expected after a groin injury because it's always worse the day after," LaDainian Tomlinson said.
But the body language was evident that the injury could compromise him in Saturday's game. It's unfortunate for the Chargers, as Tomlinson was running with ease and gobbling up yards in the win over Denver. He finished with three rushing touchdowns and 96 yards, showing a burst and cutting ability that San Diego fans have known well but seldom saw this season.
"I don't think I'll be 100 percent (this week), but we'll see what happens day-to-day, see how it goes and see what happens on Saturday," he said.
The Chargers got no favors by drawing the Saturday night game. That gives Tomlinson one less day to heal. And Tomlinson knows strained groins to shifty backs aren't good.
"It affects a great deal, especially a running back who likes to do what I do, a lot of cutting and stuff," he said. "It definitely affects you."
Someone suggested Tomlinson looked glum because of his health. Tomlinson was slowed by a sore toe earlier in the year.
"No, I think you're just reading a little bit into it," Tomlinson said. "It's a business mind-set. It's a new season and we've got a tough game this week and we're playing Saturday. We've got to be ready to play."
Coach Norv Turner has his fingers crossed Tomlinson won't be restricted.
"He should be all right," Turner said. "That will be the thing you guys ask me about most I'm sure each day. ... They expect him, as the week goes on, to get better and be able to practice and be ready to play. We'll keep a close watch on that."
--QB Philip Rivers didn't make the Pro Bowl, but one can make the argument he has had his finest season. Rivers broke Dan Fouts' team record by throwing for 34 touchdown passes this season. He also finished with the NFL's highest rating (105.5), setting another team record. Rivers will have to be on his game Saturday, especially if LaDainian Tomlinson is compromised with his groin injury.
--RB Darren Sproles continues to deliver triple-digit yardage with his returns, receptions and rushing. Sproles is being inserted more and more into the base offense, usually to be the recipient of screen passes from QB Philip Rivers. Sproles could see more playing time if LaDainian Tomlinson isn't fit.
--TE Antonio Gates is nursing a sore ankle, but tests have been encouraging. That said, Gates could be limited in practice this week leading up to the game. Gates has 14 receptions for 170 yards and two touchdowns in the past three games.
--WR Vincent Jackson has replaced Chris Chambers as the team's No. 1 wideout. Jackson has delivered the first 1,000-yard season from a Chargers wideout since 2001. He is also being used on reverses -- a longtime favorite of coach Norv Turner. Jackson gained 30 rushing yards Sunday to go with his 47 receiving yards.
--WR Malcom Floyd could return this week after missing the past two games with a collapsed lung. Floyd has come on this season, and his presence takes attention away from WRs Chris Chambers and Vincent Jackson. Floyd has 465 receiving yards and four touchdowns.
--WR Chris Chambers got back into the flow in the win over Denver with three catches for 50 yards. Chambers had been overlooked of late with the emergence of Vincent Jackson. Chambers had only five catches in the previous four games.
--ILB Stephen Cooper continues to be among the leaders on the defensive side. He leads the team in tackles and interceptions -- this despite Cooper being suspended for the first four games of the season.
--CB Antonio Cromartie sees an enticing matchup when facing Indianapolis' Peyton Manning. Last year, Cromartie had three interceptions against Manning. Cromartie has only two interceptions this year after stating that his goal was 15. He led the league with 10 interceptions last season.
--OLB Shaun Phillips needs to have a big day against Peyton Manning, so the Colts QB can't sit in the pocket and pick apart the secondary. Phillips has a team-high 7.5 sacks. Phillips has a sore knee, but he will go on Saturday.