Locker has had some bad luck early in his NFL career. Hopefully this injury isn't as serious as it looked, but the fact that he just laid there after the hit leads me to believe that it is going to be pretty bad.
For now, Ryan Fitzpatrick will take over the reigns. The Titans brought signed him because they felt like he could be a good option in a situation just like this one. Hopefully they are correct.
I will update this post as more information becomes available.