Williams out 4-to-6 weeks

The Notre Dame career of Ian Williams might be over.

The senior nose guard suffered an MCL sprain against Navy that left Williams sobbing on the sideline with a cast on his left leg. After an MRI on Sunday, Brian Kelly announced on Tuesday that Williams will be out four-to-six weeks, meaning the senior could return should the Irish make a bowl game.

Kelly said Williams' injury won't require surgery. The Irish head coach added that he didn't think the senior was injured on an illegal block against Navy, which double-teamed Williams on nearly every snap.

"Any time you lose Ian Williams, who we can say is our best defensive player, the production has to come from somewhere," Kelly said.

The Williams loss creates a next-man-in effect for three players. Sean Cwynar moves into the starting nose guard spot, Hafis Williams shifts from back-up end to back-up nose, and freshman Kona Schwenke is now backing up Ethan Johnson at end.

Schwenke has not played this season but made the trip to Navy, his first travel squad inclusion all year. Kelly said Schwenke will play this weekend against Tulsa despite the fact it will remove his red-shirt option.

The loss of Williams could come at a worse time for Notre Dame's run defense which is just one game into a brutal stretch following the loss to Navy. The Irish play four Top 30 run defenses to close the regular season in Tulsa (No. 13), Utah (No. 29), Army (No. 8) and USC (No. 18). Rediscovering the defensive form that let the Irish hold Boston College, Pittsburgh and Western Michigan to a combined 152 yards rushing was going to be difficult enough with Williams, but without the senior it may be impossible.

In other injury news, Kelly said he's "hopeful" that Michael Floyd will return this weekend but Theo Riddick remains out at least three more weeks. Floyd will practice this week.

"(Floyd) has to practice," Kelly said. "We can't sit on him."

Hamstring injuries to Carlo Calabrese and TJ Jones don't appear significant enough to sideline either this weekend. Kelly added that Jamoris Slaughter is improving but is not completely healthy with an ankle sprain and bone bruise.