Just when it appeared that the Ravens secondary had regained another option with the return of cornerback Chris Carr from an injured left hamstring, the unit may have lost safety Haruki Nakamura.

Nakamura, who has filled in as a fifth defensive back when the defense employs its nickel package, is scheduled to undergo a magnetic resonance imaging exam after suffering an injury to the posterior cruciate ligament in his right knee during a punt return in the first quarter in Sunday’s 37-7 convincing win against the St. Louis Rams.

Nakamura did not need crutches to navigate his way through the locker room at the Edward Jones Dome, but he did walk slowly and stiffly.

“There’s actually no pain,” Nakamura said. “It’s just really stiff more than anything.”

Nakamura said he didn’t know if the ligament was torn or simply bruised until he underwent the MRI. All he could he do is hope.

“I hope it’s a minor thing,” Nakamura said. “They say if you’re going to do something to any of those, it’s the PCL. They said it’s more about the muscles getting overcompensated when you injure your PCL. So we’ll see.”