Adrian Peterson injury leaves big questions

OK, I was too optimistic when I signed off earlier Saturday. We have a few issues to address, and first up is the substantial knee injury suffered by Minnesota Vikings tailback Adrian Peterson.

Peterson fell short of the dreaded "trifecta" injury to his left knee Saturday, but the team will still have some unexpected questions to address this offseason as a result. Namely: Can the Vikings build their offense around Peterson in 2012?

The Vikings confirmed late Saturday night that Peterson tore the anterior cruciate ligament (ACL) in the knee during Saturday's 33-26 victory over the Washington Redskins. Josina Anderson of ESPN and Tom Pelissero of 1500ESPN.com report that the medial collateral ligament (MCL) is also torn, but that the third primary ligament of the knee -- the posterior cruciate ligament (PCL) -- remains intact.

Still, the late timing of this injury calls into question whether Peterson will be ready for the 2012 season, which starts in less than 10 months. It's too early to talk about timetables, but that would be a quick one for a running back who relies on lower-body explosion.

Vikings coach Leslie Frazier began his tenure with plans to build a power offense around Peterson. At the very least, it's going to be difficult for the Vikings to count on Peterson's availability in September during the time in March and April when they are acquiring players to enhance their offense.

Of all the issues the Vikings had on their plate this offseason, the running back position wasn't one of them. Now it might be their most pressing.

All in all, Saturday wasn't the greatest day for the long-term prospects of the franchise. Their $100 million tailback suffered a potentially career-altering injury, an otherwise meanginless victory made them more likely to get the No. 3 overall pick in the draft than No. 1 or No. 2 and franchise quarterback Christian Ponder was again outplayed by backup Joe Webb.

Frazier will further address these issues during his Monday news conference.