Tom Brady is a six-time Super Bowl champion, three-time MVP and one of the greatest quarterbacks in NFL history. However, the 42-year-old still feels he has unfinished business he could address only through leaving the New England Patriots.

Brady wrote about his move to the Tampa Bay Buccaneers in an essay on the Players' Tribune:

"Right now, though, I have things to prove to myself. The only way is through. If I don’t go for it, I'll never know what I could have accomplished. Wanting to do something is different from actually doing it. If I stood at the bottom of a mountain, and told myself I could scale the highest peak, but then didn’t do anything about it, what's the point of that?"

Brady later took to social media to thank Patriots Nation:

My journey over the past 20 years in New England has been amazing. It’s been a long road, and I wouldn’t change anything about it. The support and love of New England fans has always been unconditional. Thank you, Pats Nation #TheOnlyWayIsThrough https://t.co/Vl2Hx6k4Gc pic.twitter.com/KyF4wMIRTc

— @tombrady (@TomBrady) April 6, 2020

Although Brady's place in the game is secure, a level of skepticism surrounds the value he can provide in 2020.

ESPN's Seth Wickersham provided a look at the factors that led to Brady's move to the Buccaneers. In general, Brady wanted a long-term commitment from New England, but the Patriots were content to let him walk rather than meet his contract demands.

That alone would provide the 14-time Pro Bowler with more than enough motivation. He might also have felt somewhat slighted by what appeared to be a small market for his services in free agency.

Brady is coming off a poor 2019 season by his standards. He threw for 4,057 yards, 24 touchdowns and eight interceptions, and he finished 16th in DYAR (defense-adjusted yards above replacement) among quarterbacks, per Football Outsiders.

He's also poised to be the oldest quarterback ever to start a full 16-game slate. Vinny Testaverde continued playing until 44 but only made seven appearances in his final year.

The uncertainty around Brady is justified, yet nobody should be surprised if he delivers at least one more monster season to further burnish his legacy.