"You hope you get to exit on your own terms. You hope to exit with a great win," said Watson, who won his only Super Bowl ring while on injured reserve as a rookie with the New England Patriots in 2004.
Watson, who turned 38 earlier this month, ranks 14th among tight ends in NFL history with 528 career receptions for 5,856 yards and 44 touchdown catches.
"I knew coming into this year that it probably would be the last year. And I think our approach was as a family that we were fortunate to come and play for another year, but you kind of know," said Watson, who spent six years with the Patriots, three with the Cleveland Browns, three with the Saints and two with the Baltimore Ravens before rejoining the Saints this offseason. "It's been great to be a part of this team and have this sort of winning at this point of my career. But the injuries add up, the body struggles more and more. And it becomes evident that it's time.
"It's always a very hard thing, but my mentality this year has definitely been to perform to the best of my ability and fight through different things."
Watson, who suffered a torn Achilles with the Ravens in 2016, has played in every game for the Saints this year with 33 catches for 371 yards and two TDs. And though he is admittedly feeling more of the aches and pains these days, he's still a chiseled 6-foot-3, 251-pounder whom Saints running back Mark Ingram referred to as "the Under Armour mannequin" earlier this year.
Watson spent more than half of his career catching passes from future Hall of Famers Tom Brady and Drew Brees, which he called "pretty incredible." And he joked that he tells them if he goes into TV or broadcasting that, "I'll always have something to talk about" because of them.
But Watson said he doesn't know what's next for him, with a number of possibilities that range from broadcasting to writing to public speaking to perhaps even politics.
A two-time finalist for the NFL's Walter Payton Man of the Year award, Watson has become a prominent national voice on social issues and race in recent years, and he has authored two books since his Facebook post on racial issues following the 2014 riots in Ferguson, Missouri, went viral.
Watson has also been an advocate for criminal justice reform, which included a White House meeting with President Donald Trump's adviser and son-in-law Jared Kushner earlier this year. He spent time in the Dominican Republic this offseason to help fight sex trafficking. And he has been a member of the NFL Players Association's executive committee, among many other endeavors.
Meanwhile, he and his wife, Kirsten, are expecting twins in the spring -- which will give them seven children. Their family was featured on an NFL Films segment, during which Watson first revealed his plans to retire.
Watson said one of his fondest NFL memories was being elected as a captain with the Saints in 2015. And when asked what he hopes his legacy will be, he gave a lengthy response.
"I hope my legacy is that I tried to make every place better that I went to and that I grew as a player and as an advocate and as a citizen as my time went on. ... I want people to be drawn and to look at the Lord when I do certain things," Watson said. "I wanted to be somebody that's good for justice, and that comes in all forms, when you talk about social justice or criminal justice, standing for life in the womb, standing for those who are sex trafficked or people who are refugees, or whether you're wealthy or poor, treating everyone with equity, treating everybody right.
"I want my legacy to be somebody who loved his wife and somebody who loved his kids and tried to lead his family, and encouraged other guys that they have what it takes to be the men that they're called to be. ... And I want to be somebody that was reliable, that a coach could count on. A guy that when you put him out there, he did his job, whether it was with flash or without flash, he could be reliable and dependable on the field."