Eric Branch is reporting the San Francisco 49ers are hopeful that Marcus Martin "only" suffered a dislocated knee cap. The word "only" is used because the alternative includes torn knee ligaments.

There is hope #49ers rookie C Marcus Martin "only" had a dislocated kneecap on Sunday, per source. Third-round pick will have MRI today. — Eric Branch (@Eric_Branch) August 25, 2014

The recovery time will depend on whether or not it is a partial or full dislocation, and whether or not there is any additional ligament damage. We'll have some thoughts from socalisteph on this, but in the meantime, I did find this article discussing partial dislocations. If it ends up being a partial dislocation, an orthopedic surgeon said recovery time can be 4-6 weeks. If it's a full dislocation, it would seemingly be longer, and if there is ligament damage, it would be even longer.

Martin suffered the injury at the 11:32 mark of the fourth quarter while playing center. He went down and was in visible pain. Eventually he was carted off, and the general word was it was a knee injury. Following the game, Martin tweeted this out:

What don't kill me , will only make me stronger ! I'll be back better than ever before , thank you… http://t.co/s0JaXwJ1hd — Marcus Martin (@TheRealDoubleMs) August 25, 2014

Jim Harbaugh is meeting with the media at 2:45 p.m. PT. I don't expect many details, but the MRI could be done at that point. We'll see if we get anything specific from Coach Harbaugh.