"Some Chicagoans are probably happy to hear I'm finally stepping away and getting my body right," Long wrote on his official Twitter account. "Some Chicagoans may be sad to hear this. Either way [you] feel about it, I want [you] to know how lucky I am to have spent time in your city. I became a man while playing in Chicago. Thank you."
Drafted No. 20 overall by the Bears in 2013, Long missed just one game over his first three seasons but appeared in just 30 regular-season contests over the past four years.
Long, 31, suffered a gruesome ankle injury in 2016 that cost him the final eight games that year and the first two games of the 2017 season. Long ended up missing six games in 2017 with a variety of ailments, undergoing neck, shoulder and elbow surgeries in the offseason. He returned in time to start the Bears' first seven games the 2018 season before Chicago once again shut him down before his return in Week 17.
Long opened the regular season in good shape but suffered a hip injury during practice leading up to the game against the Minnesota Vikings on Sept. 29. He was inactive for that game but returned to the starting lineup against the Oakland Raiders in London on Oct. 6.
After the loss to the Raiders -- a game that Long played all 56 possible snaps on offense -- the Bears decided they would be better off on offense without Long and promptly placed the veteran on injured reserve yet again.
Long took a massive pay cut last offseason and had an option year left on his current restructured deal.
General manager Ryan Pace was noncommittal about Long's future during the club's recent year-end news conference.
"We think the world of [Long]," Pace said on Tuesday. "It's unfortunate he's had a handful of injuries. He's tried to battle through all of them. Kyle does have an option in his contract that we got to look at. That will be one of the decisions, one of the many decisions, we have to make on him. But I feel bad for all the injuries he's tried to overcome. That was a decision we made at the time. Then we'll have to make another decision this offseason with his option."
Long was named to three Pro Bowls and played three positions (right guard, right tackle, left guard) over the course of his Bears career.