Wanderer

Arm strength is coachable, both strictly via technique and through strength and conditioning. Mac's arm is certainly no worse than Brady's was in 2000. Brady's arm was noticeably better with just one off-season in a pro strength and conditioning program, but didn't become a strength until probably between the 2005 and 2006 seasons. I'd go so far as to say I'm not 100% certain Belichick makes the move to get Moss if Brady didn't show the arm strength development he showed in 2006. Brady's arm didn't become a plus/differentiator until after he got sidelined for all of 2008. NFL QBs rarely come into the league with as strong an arm as they will eventually have at their physical peak. Mac's arm is currently maybe slightly below average. And frankly, what I've seen of his physique implies that he'll benefit more than is typical from professional strength training. My guess would be that his arm will end up being slightly above average, but it could be top 25% in a few years. So I suspect he'll have enough arm for the accuracy on his deep balls to be improved. As to his mobility, it's not a strength, but there are types of mobility. Pocket mobility is the most important, and is very much coachable. He's not a statue - he moves around the pocket fairly well, and already better than early in the year. And his straight line speed is actually not bad. He ran a 4.7 at the combine. That speed isn't going to change much, but as he gains experience and improves his diagnosis and processing speed (100% coachable) he will improve in terms of when he chooses to run, and how he does it. He's already been very successful in scrambling for 4, 9, 13 yards when he needs to. He needs to improve at sensing the rush (especially from the outside), knowing when to throw the ball away, not hesitating before he takes off, accounting for the speed and athleticism of NFL defenders, knowing when and how to slide, and keeping in mind where the sticks are. All of those are coachable, and will make his scrambled more efficient and effective. I'll also add that based on what I've seen, the scrambling he has done has been made more effective because defenses don't seem to respect that he can do it. It becomes just one more bullet in his "take what the defense gives you" gun.