Tom Brady is surprised by the mental energy he needs to put in to learn a new playbook with the Tampa Bay Buccaneers.

"It's been different having the opportunity over this time to move and to, for example, study my playbook -- I mean I really haven't had to do that in 19 years, so you forget, 'Man, that's really tough,' like all of the different terminologies," Brady said Thursday. "You're going back a very long time in my career to really have to put the mental energy in like I did. I have to work at it pretty hard physically, still. I put a lot of time and energy into making sure I'm feeling good in order to perform at my best, but mentally I think that's been the thing that's obviously had its challenges."

Brady will spend time collaborating with Bruce Arians and offensive coordinator Byron Leftwich.

"I think conversations we probably would've had in April, we're having now," Brady said. "I think that part has been challenging too, but the only thing you can do is adjust to the situation, adapt the best way you can [and] put as much time and energy now as we can into it. I think the reality is, the clock is ticking on everybody. We're going to have to work as hard as we can and not waste any minutes of any day trying to get used to one another. [We need to] embrace the challenge and see it as an opportunity to see what we can become."