That means, theoretically, Brady and coach Bill Belichick plan to dominate the AFC East and keep New England in title contention until 2017. Brady will turn 35 in August.
But five more years? That is an eternity in the NFL in which the average career span is approximately 3-4 seasons. Does Brady have enough in the tank to play 17 years at such a demanding position?
According to the Elias Sports Bureau, only four quarterbacks in NFL history have started on opening day at 40 or older. Warren Moon (41) was the oldest, followed by Brett Favre (40), Vinny Testaverde (40) and Johnny Unitas (40). Brady wants to become the fifth player to accomplish that feat.
Former quarterback and ESPN analyst Trent Dilfer played 14 seasons in the NFL and believes Brady will reach that goal. According to Dilfer, the key to quarterback durability is the lower body, not the upper body.
"What goes first with quarterbacks is their legs. Once you lose your legs, you kind of lose everything else," Dilfer explained. "I remember Kurt Warner talking about that late in his career, and obviously I experienced it. Every quarterback experiences it. I think Tom works hard enough to maintain the leg strength he needs to be as precise as he is, and I think he's a competitor that if he puts something in his mind that he's going to do something, he's a guy that goes out and does it.
"There's very few people in sports like that, talk about the Kobe Bryants and the greats in all sports. I think Tom is right up there. When he puts his mind to something, he's going to do it. So I fully expect him to be playing at 40 if he says he's going to."
It's hard to say when that window will close for Brady, who will lead the Patriots (14-3) in Sunday's AFC Championship Game against the Baltimore Ravens (13-4). He's proved over the past dozen years that as long as he's healthy, he's an elite player. Brady is an MVP candidate this season and by far the best remaining quarterback in the playoffs.
A case can made that Brady's three best statistical seasons occurred after 30 -- in 2007, 2010 and 2011. He also is coming off a record-tying, six-touchdown performance in a 45-10 playoff victory over the Denver Broncos. It was one of his top single-game performances.
Brady projects to be an elite player for at least the next two or three seasons. Injuries are probably the only thing that can derail him at this stage of his career.
Brady had reconstructive knee surgery and missed 15 games in 2008. Otherwise, he has had a clean bill of health. Outside of 2008, he has missed just one start since taking over the job in 2001.
"If anybody can pull it off, it's Brady, but like we saw with Peyton Manning, he could break down easier [with age] too," Matt Williamson of Scouts Inc. said. "Manning may never be the same. He may never play at that same high level. Who knows? If Brady hits one stumbling block like Peyton did, all of a sudden 40 is a long way away for him. But nobody is playing better than Brady right now."
Brady has been fortunate with pass protection throughout his career. He has been sacked 26 times or fewer in six of the past seven seasons.
Former Patriots linebacker Tedy Bruschi was a longtime teammate of Brady's and knows firsthand the importance of protecting the veteran quarterback. Brady is a classic pocket passer who moves well in the pocket. But he doesn't have the ability to run away from defenders.
"As players progress up into the years, the more shots you take, the shorter the second half of your career will be," Bruschi said. "And I think Tom Brady will play as well as his offensive line, his protection, allows him. I think he's shown over the course of the last few years that there are the usual [ailments], they're becoming normal now. Late in the season, where he had a rib or a shoulder or various injuries like that over the course of a season.
"You end up accumulating some damage, especially as a quarterback, because you're the most sought-after hit in terms of the defensive perspective. So if he can be protected, I think that goal is possible. He can play as long as he wants to."
Brady currently is playing with a left shoulder (non-throwing) injury that has to be managed during the playoffs. This week Brady sat out of Wednesday's practice to rehab and watched extra film of Baltimore's defense.
An under-the-radar aspect of Brady's longevity could be the development of tight ends Rob Gronkowski and Aaron Hernandez. Both have been tremendous weapons and security blankets for Brady in their second season together.
Throwing in the middle of the field is the quickest and easiest completion for quarterbacks. It also keeps the pass rush at bay.
"They're obviously a huge part of what we do," Brady said of his tight ends this week. "They are on the field quite a bit and they’ve been healthy so it’s been good to have them both out there. ... They're pretty good with the ball in their hands and break a lot of tackles so that’s definitely a plus for us also. We have a lot of yards after catch this year, and those two guys certainly do a great job with the ball in their hands."
Patriots owner Robert Kraft still remembers when the late-round draft pick came to Foxborough as a long shot in 2000. Kraft shared a great story about his first encounter with Brady this week.
"I still have the image of Tom Brady coming down the old Foxboro Stadium steps with that pizza box under his arm, the skinny beanpole," Kraft said. "When he introduced himself to me and he said, ‘Hi, Mr. Kraft,’ and he was about to say who he was and [I said], ‘I know who you are, you’re Tom Brady, you’re our sixth-round draft choice.’ He looked me in the eye and said, ‘I’m the best decision this organization has ever made.' It looks like he could be right, although hiring Bill Belichick, I think, also has been a pretty good decision."
Brady's Hall of Fame legacy is secure. If he retired today, Brady already would be among the top quarterbacks ever to play the position. He has three Super Bowl rings and could tie his childhood hero -- Joe Montana -- for the most playoff victories (16) with a win over Baltimore Sunday.
But the difference between being a top-five quarterback and the greatest ever could come down to these next five years. Brady can tie Montana (four) and Terry Bradshaw (four) for the most titles in these playoffs. But if Brady plays through age 40, he has a legitimate shot at being the winningest quarterback in NFL history.
"I'm really happy that we have him as our quarterback," Kraft said. "I hope we have the best quarterback and coach in the history of the game. I guess to prove that, we have a little more execution that we have to do over the next few years. I certainly hope we do it."