Given that GB was a high profile get for USF, I would imagine that there was some tangential discussion about him starting - maybe not a guarantee, but something like, if you come in and compete, your chances are extremely good
Also, I have to figure that the staff wanted to keep Timmy, so a corresponding conversation should have happened with him at the same time
As you stated, somewhere there was a misunderstanding, otherwise, Timmy probably would have transferred when the GB signing occurred