Skins' Guice has knee injury; Peterson back in mix

ASHBURN, Va. -- Redskins running back Derrius Guice suffered an injury to his right knee Sunday and could miss some time, according to coach Jay Gruden, potentially paving the way for Adrian Peterson to get more playing time in Washington's crowded backfield.

Gruden said Guice felt soreness in his knee after the game and was undergoing an MRI on Monday afternoon. Gruden is not yet ready to rule out Guice for Sunday's game against Dallas.

Even if he is fine, Gruden said there's a chance they would still keep Peterson active, especially if they have concerns about Guice's durability. Peterson was declared a healthy inactive for the first time in his career before Sunday's 32-27 loss to…