Injured defensive tackle Nick Fairley might not return for the Detroit Lions this season.

While head coach Jim Caldwell is not ruling him out, he called a report that Fairley will be one month with a right knee injury “didn’t come from my office.”

Caldwell said Fairley’s status will be determined down the line. The Lions are off this week after rallying to beat the Atlanta Falcons 22-21 at Wembley Stadium in London. Top reserve C.J. Mosley is also unavailable. He was sent home from London and suspended two games for violating team rules.

Fairley has a history of weight management issues, though Caldwell insisted at his press conference Tuesday that the Lions are not “losing sleep” over Fairley’s physical condition.

Defensive tackle Ndamukong Suh ran into Fairley just as Fairley was getting to Falcons quarterback Matt Ryan in the second quarter Sunday.

“How long it’s going to be, we’re not quite certain,” Caldwell said.

ESPN Chicago reported Fairley has a sprained posterior cruiciate and medial collateral ligament in the knee.