Vikings cornerback Cedric Griffin will undergo an MRI today after injuring his right knee in Monday night's loss to the New York Jets.

Griffin was hurt in the second half and left the locker room at the New Meadowlands Stadium on crutches.

This comes after Griffin returned in Week 3 after suffering a torn anterior cruciate ligament in his left knee in the NFC title game last January. Griffin spent all of training camp on the physically unable to perform list but showed enough progress that he began the season on the 53-man roster.

"It's something new," said Griffin, who declined to go into any detail as he departed the stadium on Monday. Vikings coach Brad Childress will hold a news conference later this afternoon so there is a chance he will provide an update on Griffin's status. There is concern the injury could sideline Griffin for an extended period.

The Vikings did get some good news as wide receiver Sidney Rice is off crutches. Rice had surgery on his hip in August in Vail, Colo., and was scheduled to have a follow-up exam on Monday. Tight end Visanthe Shiancoe put a picture of Rice on Twitter today that showed him without crutches. Rice remains on the physically unable to perform list and must stay there for the first six weeks of the season.

 Griffin was held out of the first two regular-season games before making his debut and playing the entire game against the Lions on Sept. 26. If Griffin is lost for an extended period it would be another blow for a cornerback position at which the Vikings have been shorthanded for much of the season.

Griffin and rookie Chris Cook both missed the first two games, meaning the Vikings used Antoine Winfield, Lito Sheppard and Asher Allen as their corners. Cook had torn the meniscus in his right knee in the preseason and didn't return until the Lions game.

At full strength, the Vikings used Winfield and Griffin as their starters at the left and right corner, respectively, and Cook moved to left corner so Winfield could slide inside in nickel situations. But Cook suffered a torn meniscus in his left knee against the Lions and is out again.

Cook was optimistic last week that he wouldn't be sidelined as long this time because the tear in his meniscus was not as severe.