What if Brady loses?

His legacy is set. It was carved in stone years ago.

Everything that Tom Brady has done since winning Super Bowl XLIX has been gravy.

When Brady won three Super Bowls in his first four full seasons as a starting quarterback, he produced the most recent NFL dynasty and proved himself as a winner early on.

When Brady captured another Super Bowl victory two seasons ago, he proved that age would not stop him from another championship.

In the 11 years since winning Super Bowl XXXIX, Brady has made it to three more Super Bowls and only won one of them. However, his achievements along the way have been incredible.

                        -Brady will play in his sixth straight AFC Championship Game. No other AFC team has ever appeared in six consecutive conference championship games. In an age when there has not been a back-to-back Super Bowl Champion since the Patriots in XXXVIII and XXXIX, Brady and New England are constantly in contention for the Lombardi Trophy.

                        -Even with the “drought” in between Super Bowl victories, Brady accomplished plenty of impressive postseason feats. He is the all-time leader in games played, pass attempts, pass completions, yards gained, 300-yard games and touchdowns in the playoffs.

                         -That success doesn’t end in the postseason. Brady will be the all-time winningest regular season quarterback with four wins next season. In his 14 healthy seasons as the Patriots quarterback, Brady has never won fewer than nine games.

Deflategate be damned, Tom Brady did not need low pressure footballs to whoop the Indianapolis Colts. No matter how inflated the footballs were, the Colts were not going to the Super Bowl in 2015.

Now, at 39, Brady is in the twilight of a Hall-of-Fame career and has a problem. Of the aforementioned six consecutive AFC Championship Games, Brady is only 2-3 prior to Sunday’s meeting with the Pittsburgh Steelers. If the Patriots lose on Sunday, it will be the second consecutive year that they have failed to reach the Super Bowl.

When the 2017 regular season starts, Brady will be 40. Only 16 other quarterback-only players played at 40 or beyond.

Brady will play next season, he is under contract until 2020, but will an AFC Championship Game loss be his undoing?

Consider this past season. Sure, Brady set the touchdown-to-interception ratio record with 28 touchdowns and two interceptions. Very impressive after missing the first four games of the season.

However, those stats do not tell the full story.

Who is the best quarterback that Brady faced this season? Joe Flacco? Andy Dalton? Tyrod Taylor? Are any of them considered elite?

How will Brady do against a Steelers defense that has improved since he faced them in Week 7? Three games after Pittsburgh lost to New England, the Steelers bumped Jarvis Jones from the starting outside linebacker spot and replaced him with James Harrison. Since then, Harrison has recorded 5.5 sacks in eight games as a starter. Jones only sack of the season came on New Year’s day against the Cleveland Browns when Harrison was resting. Brady is going to feel the blitz the entire game.

The Patriots are favorites in this game for a reason. New England is 2-1 in home games during its AFC Championship Game streak. That said, if the Steelers win and the Patriots move to .500 at Gillette Stadium during the streak, what is their excuse? Sure, one of those times that they moved on they won a Super Bowl, but the failures outweigh the success.

Look, no one is denying the possibility that Patriots can get back to the AFC Championship Game, but let’s say, hypothetically, that the Patriots lose this Sunday and don’t return to the AFC Championship Game next season. Does that mean that it’s time to slowly move on from Brady?

As much as the media is hyping up Jimmy Garoppolo trade rumors, the fact remains that Garoppolo is still under contract with the Patriots until 2018. If New England wants him to be Brady’s successor, it can see how Brady does in 2017, then make a decision on whether or not to extend Garoppolo, if the plan is to make him Brady’s successor.

Here’s a problematic scenario for New England: Brady plays well in 2017, but suffers a catastrophic injury that will affect his ability for the rest of his career (see Derek Jeter 2012 ALCS Game 1 injury). It does not matter when the injury occurs, unless Garoppolo has been traded before it.

Let’s assume Garoppolo is still a Patriot. Does New England overpay Garoppolo because it knows Brady’s end is quickly near? Does it refuse to overpay Garoppolo and tank for a high talent quarterback early in the Draft? There is no easy answer.

Regardless of what happens Sunday, Tom Brady will be the Patriots’ starting quarterback to start 2017. Whether he can hold onto that job or not at 40 remains to be seen.