On Sunday, 49ers linebacker Patrick Willis suffered a hamstring injury. After the game, the injury was believed to not be serious.
Willis underwent an MRI on Monday. Per a league source, surgery will not be needed for the hamstring strain, and the 49ers could rest Willis on Sunday at Arizona.
Eight days later, the 49ers play the Steelers on Monday Night Football.
Adam Schefter characterizes the injury as a Grade 2 strain. He adds that Willis could miss some time.
The 49ers played well against the Rams without him, but as they try to nail down the No. 2 seed, they’ll need Willis to be at 100 percent.