Coach Jeff Fisher says that if Keenum is cleared on Friday, he would be the backup against the NFC West-leading Arizona Cardinals on Sunday.
Foles threw three interceptions, one of them returned for a touchdown, in a loss at Cincinnati last week.
Keenum landed hard on the back of his helmet near the end of a loss at Baltimore two weeks ago, but was in the game for two more plays. He was diagnosed with a concussion after the game.
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