The Vikings placed running back Adrian Peterson on injured reserve Monday. The all-pro is expected to miss eight-to-nine months after tearing his ACL and MCL in his left knee during the third quarter of Saturday's win over the Redskins. Running back Caleb King was activated from the practice squad, along with tight end Mickey Shuler.

It's been nearly three months since Adrian Peterson tore his ACL against the Redskins. There hasn't been a lot of news about Peterson's recovery since he went down, but he is progressing well.

The Vikings say nothing is set in stone, but injured running back Adrian Peterson is on target for a Week 1 return in 2012 following surgery on his torn ACL.

Despite playing through an ankle injury and eventually blowing out his knee, Vikings running back Adrian Peterson came in at No. 8 on NFL Network’s “Top 100 of 2012.”

No one asked him to do it, but Vikings running back Adrian Peterson worked out for reporters today to show how far he’s come since tearing his ACL last December. Afterwards, he said he feels no pain...and will be “surprised” if he misses Minnesota’s season opener in September.

Adrian Peterson's season has been so good so far that he's making people forget he tore his ACL less than a year ago. Peterson is 14 yards from passing his 2011 total, and is on pace for 1,700 yards.

Adrian Peterson tested his reconstructed left knee by running inside the Vikings' practice facility at Winter Park last week. The goal of the test run was to judge Peterson's movement. Leslie Frazier told reporters Tuesday that head trainer Eric Sugarman was "really impressed with his movement and the things he was able to do."