The San Francisco 49ers place nose tackle Ian Williams on the physically unable to perform list.

Williams broke his leg last season against the Seattle Seahawks.

He's had four surgeries on the leg.

It was Williams' first career start when he got injured.

A former Notre Dame player entering his fourth season, Williams has played in six games for the 49ers.

Williams can be activated at any time.

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Aaron Wilson covers the Ravens for The Baltimore Sun