Well DUH???? Of course he knows the offense, it is the same as he ran in college. Did you think he was going to forget his offense from last year in a few weeks? Look I love Tannehill, but knowing the offense doesn't prove anything. Knowing the defense is the problem. In college DBs gave 10 yard cushions, defenses walked up and showed you what they were in, mental errors and balls thrown slightly off target were usually dropped by college defenses, in the pros it's a different story. RT is going to see fronts that change after the snap, he is going to see DBs show one thing and do another, a WR that he knows is one on one is still covered at this level and it is going to take a perfect throw to get a completion, and at the NFL level almost every mistake equals a interception.
EVERY QB knows the offense by the time they get to training camp. The had better any way, knowing the offense and being able to manipulate a defense is two different things. I am not saying RT won't be able to succeed, I am saying it won't happen early this year if at all. Knowing the offense is not that big of a deal.