Mathews wore a protective boot on his injured left ankle coming off of the field at the end of practice. But he says that everything is fine. Mathews did not practice most of last week but still played against Kansas City, rushing for a season-high 144 yards on 24 carries.
"I'm fine," Mathews said. "I'm good. You just have to stay in it mentally."
Along with Mathews, receiver Eddie Royal (toe) did not practice. But both are expected to play Sunday in Cincinnati.
Defensive linemen Sean Lissemore (shoulder) and Kendal Reyes (ankle) were limited in practice.
Outside linebacker Thomas Keiser did not make himself available to reporters in the locker room after practice to discuss his recent arrest.
San Diego coach Mike McCoy said the team is handling Keiser's situation internally. Keiser did practice Wednesday and is expected to play on Sunday.
"We discussed it early Monday morning -- that's the first thing we did in the team meeting," McCoy said. "We addressed it, said 'Here's how we're handling it.' And we're moving on."
Keiser, 24, was arrested over the weekend on a misdemeanor battery charge after an altercation with another man in a restaurant that turned into a fight Sunday after San Diego's overtime win over Kansas City.
"Thomas is our teammate, our family and we support him," safety Eric Weddle said. "And until they figure all of that out we're worried about the Bengals."