Just a wild guess but he might be starting there because of the weather down in Florida will be much better for someone coming back from a 2nd major leg injury. He hasnt played in cold weather since sometime in 2007,he missed his senior year in high school,played in the GCL in 2008,rehabbed all last year in Bradenton
Actually, he likely tore his ACL in High School, opted not to have the surgery, and was playing with the ACL torn. (Hines Ward tore his in high school and never had it fixed, so some people have enough stability in their knee without the ACL.) I remember reading about some miracle recovery from his high school injury (obviously, I don't believe in miracles). I would guess that his knee went out again due to the lack of the ACL and he then opted for the surgery.
Point being, he really has had one injury. And having the surgery young will do wonders in the recovery, as long as he didn't do major damage to the cartilidge as well.