But that doesn't mean he wasn't working.
"I'm doing whatever they ask me to do," Mathews said. "Whatever they need me to do. I'm here early, and I'm staying here after."
Mathews did not participate in practice on Wednesday due to an ankle injury suffered against Oakland last week. Mathews left the game in the second half to get treatment on his ankle, but later returned. Mathews wore a protective boot on his left leg as he left the practice field.
San Diego coach Mike McCoy indicated once again that Mathews should play on Sunday.
"I expect him to play," McCoy said. "It's as simple as that."
Mathews also was a limited participant in practice last week on Wednesday due to a foot issue, but practiced the next two days and played impressively against Oakland on Sunday.
Mathews said he aims to play a full, 16-game season for the first time in his four-year NFL career.
"100 percent," Mathews said. "That's what I want to do is be 100 percent this year in the games. So that's what I'm going to try for."
Mathews ran for 55 yards and a touchdown in a 41-38 win at Kansas City earlier this season.
Cornerback Shareece Wright (foot) and receiver Eddie Royal (toe) also did not practice for San Diego. Royal has not practiced on a regular basis since injuring his toe against Indianapolis on Oct. 14, but he's only missed one game since the injury.
McCoy said he expects Wright to play on Sunday.
Guard Jeromey Clary was a limited participant due to a hand injury. McCoy said Clary's limited status for practice was more precautionary, and that he could have practiced fully.