Ravens safety Kendrick Lewis is hoping his knee injury isn't a serious one. Ed Szczepanski The Baltimore Sun

Ravens safety Kendrick Lewis will have an MRI Monday to determine the severity of the knee injury that forced him out of Sunday's loss to the 49ers.

Lewis, who was helped to the locker room by the team's medical staff, was seen on crutches after the game. He was injured in the third quarter while attempting to tackle receiver Anquan Boldin.

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Head coach John Harbaugh doesn't believe the injury is serious, but was unable to give a timetable after the game.

"We'll know more tomorrow when he gets the MRI, but I can't give that kind of indication right now," Harbaugh said after the game via The Baltimore Sun.

The Ravens could ill afford an extended absence for Leiws as injuries continue to mount for the secondary. Reserve safety Terrence Brooks was already out with a thumb injury and Matt Elam was lost for the year in preseason, leaving Brynden Trawick and Anthony Levine as the only other backups on the depth chart. Corner Lardarius Webb (thigh) missed Sunday's game and Will Davis was lost for the season last week with a torn ACL.

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