Even coming off ACL surgery I'd rather have Cook. He looked amazing so far this year, and should easily retake the starting/lead role next season. ACL's are getting easier (that's probably not the right word) to return from. Higher rate of success upon return, rather. Henry is at best stuck in a timeshare with Murray, and I don't think henry will take over as lead back unless Murray gets hurt. Titans realize they have two good backs that aren't expensive, and Murray has earned the right to at least half the load at worst. Murray still has two years on his contract, but the Titans do have an early option out after this season, but I don't see them cutting bait because Murray is only $6MM/yr and he's plenty proven his worth there.
We need Henry to get the volume Cook does to prefer Henry over Cook. I don't see that happening in the next year or two, so take Cook.