"It is his life. Everyone has the right to choose what they want to do," Brady said on WEEI's The Greg Hill Show. "He had a great career and he was a great player. Everybody wishes they could be healthy all the time. It is a contact sport and he's certainly had his fair share of injuries, so guys retire at different times. Some at the end of the season, and I have seen a lot of guys retire before the season gets going and this is just one of those examples."
There's a stark contrast to be made between Brady and Luck, who retired at age 29 on Saturday due to mental and physical fatigue over the numerous injuries he's suffered during his NFL career. Brady is entering his age-42 season and has suffered only one major injury in his career—a 2008 ACL tear that cost him nearly that entire campaign.
Luck, by contrast, missed nine games in 2015 and the entire 2017 season due to injuries. He also played through numerous ailments that left him almost consistently below 100 percent health.
Brady has said he plans to play until at least 45 years old on numerous occasions. He credited his support system with helping him prolong his career:
"I think it's everything. There's definitely a physical element. There's definitely an emotional element. I think there is a mental element. Everything in my view really has to come together for you to be the best version of yourself as a player, and it takes a lot of support. It takes a lot of people. You see certainly, you can see me as an individual doing that. I have the support of my teammates, my coaches, my family, my friends, Alex (Guerrero), my training system. All those things really need to come together in order to continue to achieve.
"It feels great when you have that support because a football season is like a marathon. There's moments where it is very challenging whether it's physically, emotionally, or mentally — you need somebody to help you push through the hard parts because it's not all easy. It's a great challenge, but it is very rewarding when you meet the challenge, too."
If anything, the contrast between Brady and Luck makes them both look like extreme outliers on the spectrum. Brady is continuing to play at a level we've never seen before for a quarterback his age; he's already the oldest league MVP in history and is coming off a Super Bowl victory. Luck walked away from a sport that would have paid him hundreds of millions of more dollars over the course of the next decade if his body would have allowed.
There's no modern equivalent of a 29-year-old Pro Bowl quarterback retiring or a 42-year-old quarterback still ranking among the game's best. It just goes to show how much luck and circumstance can help a player's career.