The San Diego Chargers say center Nick Hardwick sustained a concussion as well as a stinger in Sunday's playoff victory over the Cincinnati Bengals.

Rookie coach Mike McCoy, who's loath to discuss injuries, says the concussion was diagnosed after the game. The first word of that diagnosis came when the team announced its injury report after practice Wednesday.

It's not known whether Hardwick will be able to play in Sunday's divisional round game at Denver. He must pass certain tests in order to be cleared to play.

Running back Ryan Mathews also didn't practice Wednesday and was in a walking boot to protect his injured left ankle. He came out of Sunday's game in the third quarter.

Mathews ran for 127 yards and one touchdown in San Diego's 27-20 upset victory in Denver on Dec. 12.

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