Coach Pete Carroll said Penny (knee) had an MRI and isn't expected to require surgery, Gregg Bell of The Tacoma News Tribune reports.
Penny didn't practice this week and has been ruled out for Sunday's game in San Francisco. His absence should free up more work for Mike Davis behind starter Chris Carson, though it's also possible Carson or J.D. McKissic handles some of the vacated snaps/touches. While the rookie doesn't seem like a great bet to make it back for Week 16, the Seahawks hope he can play again this season.