Most rookies deal with growing pains and Troup was no exception.
For some, it's the speed of the game. In college, the fast players really stand out. In the NFL, everyone decent has speed. CJ Spiller for instance, found that he can no longer outrun people around the corner and he suffered. His future success will depend on how he adapts to things like reading and following blocks, hitting the hole with speed and also being able to run inside.
For most linemen, one of the biggest issues is strength. In college, they can easily overpower the guy across from them. In the NFL, no such luck. That's why scouts always make a big deal about a guy's frame, because it shows how much muscle they can potentially add. Troup seems to have a good frame to add size and strength, so that's a definite positive.