INDIANAPOLIS (WISH/AP) — Calling it “the hardest decision of my life,” Colts quarterback Andrew Luck said Saturday night he is retiring as he continues to deal with an ankle injury.

He made the announcement in an impromptu, 25-minute news conference after the Colts lost a preseason game to the Chicago Bears 27-17 at Lucas Oil Stadium.

“I’m in pain, I’m still in pain,” Luck said. “It’s a myriad of issues — calf strain, posterior ankle impingement, high ankle sprain. Part of my journey going forward will be figuring out how to feel better.”

Team owner Jim Irsay said that “part of our heart is broken tonight.”

Adam Schefter of ESPN first reported the quarterback’s retirement in a Saturday night tweet during the game against Chicago where Luck was on the sidelines.

The 6-feet-4 quarterback from Stanford last practiced with the team July 28 at training camp in Westfield. The Colts already had said his lower leg injury probably would keep Luck out of the entire preseason.

Luck was initially diagnosed with a strained calf in March and did not participate in any of the team’s offseason workouts. When training camp opened, he was limited to individual drills and seven-on-seven but no full team drills. But when the pain persisted, Luck returned to rehab and was only permitted to run the starting offense in walkthroughs.

“I feel quite exhausted. … I feel tired and not just in a physical sense,” Luck said Saturday.

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He said he started having the conversation about retiring a couple of weeks ago when no progress was being made on his ankle injury.

Luck said he had planned to tell his teammates after the game about his decision, followed by a 3 p.m. Sunday news conference. The Colts locker room was closed to the media after the game.

The Colts selected the 29-year-old quarterback as the first overall pick in the first round of the 2012 NFL Draft. He scored 171 touchdowns in his career, according to the team’s website, and leaves the Colts with a 57-37 win-loss record, according to football databases. 

The news spread quickly among fans at Lucas Oil Stadium. Luck said in the news conference he was hurt by the booing fans as he walked off the field during the preseason game.

In a separate news conference after the preseason game, Colts General Manager Chris Ballard said, “For those people that booed tonight, it’s an emotional time and I understand that. … This man had done a lot for Indianapolis and the Indianapolis Colts.”

In his support of the city, Luck hosted an NFL Play 60 event with Indianapolis Public School students, served as a co-spokesperson for the “COLTSTRONG, LIBRARYSTRONG” campaign for the Indianapolis Public Library and visited Riley Hospital for Children at IU Health to spread cheer during the holidays.

Coach Frank Reich said. “There’s a saying in football that everyone knows and everybody lives by, it’s next man up and even though this situation is unique, no one is exempt.”

Luck also noted in the news conference he’d been in pain and rehabilitation for four years.

In September 2015, he sprained his shoulder and sat out two games after a Week 3 game against the Tennessee Titans. 

In November 2015, a couple of days after a win over the Denver Broncos, the Colts announced Luck had abdominal injuries that later were determined to be a lacerated kidney plus multiple muscle pulls. He didn’t return for the rest of the season.

In the 2016 season, Luck sat out one game in November due to a concussion.

In January 2017, Luck had shoulder surgery. He didn’t return to the field until Aug. 9, 2018, for a preseason game and Sept. 9 for a regular season game.

He played his last game for the Colts in the AFC Divisional Playoffs on Jan. 12. His last NFL game was the Pro Bowl on Jan. 27.

Luck said he has faith in the next quarterback who will lead the Colts to their first regular season game on Sept. 8 against the Los Angeles Chargers.

“Jacoby Brissett is an awesome dude … bright and sharp,” Luck said. Last year, he said, he was “very jealous and resentful of this fun, happy dude who was in my spot. I could not have been more wrong (about Brissett). I cannot wait to support him and see him lead this team.”

Ballard said he’s excited to watch Brissett play.

“We’re not going to ask Jacoby Brissett to be Andrew Luck.”