The entire football world is wondering how long Tom Brady is going to play for.He is already one of the greatest quarterbacks of all time. He surprised many by playing at a high level into his late 30s. Then, he topped that by continuing the play into his early 40s.So the question remains, how long can he go on like this and will he?His trainer cast some light on the subject in a recent interview. He believes the next level for Brady is to maintain this level of play until he is 45. That would give the 42 year old Michigan alum another 3 years under center.Brady could actually go on longer than that. The trainer kept talking about at a high level. Thus far there is no drop off in Brady's game. Could be still play at 46 or 47 while being 80% of his former self? That is still a very good football player.