Left guard Mike Iupati suffered a sprained MCL when teammate Frank Gore ran into the back of his left knee Sunday in New Orleans, according to a source with knowledge of the injury. Iupati left the game in the third quarter and was carted into the locker room. Adam Snyder finished the game at left guard.
Iupati had an MRI on the knee today. His prognosis is unknown at this point, but he is likely to miss at least Monday's game against the Redskins. If that's the case, it will be the first time one of the 49ers starting offensive linemen has missed a start since the beginning of the 2012 season. Snyder is the favorite to start in Iupati's place, although Daniel Kilgore has filled in at times during the season.
Still, Iupati will not need surgery and the injury is not expected to end his season. In last year's game against the Saints in New Orleans, the 49ers lost both running back Kendall Hunter (Achilles') and receiver Kyle Williams (ACL) for the season.
Iupati was one of the top guards in the league a year ago and was named to both the Pro Bowl and All-pro team. He had surgery on his shoulder in the offseason and has been battling an array of issues - including shoulder and elbow injuries - this season. He briefly left last week's game against Carolina with a knee injury but returned to the contest.
There are three grades on MCL sprains, each requiring a longer recovery period. Running Back LaMichael James, for example, suffered a Grade 2 sprain in late August and missed a month.
-- Matt Barrows