INDIANAPOLIS -- In a shocking development Saturday night, Indianapolis Colts quarterback Andrew Luck announced his retirement from the NFL, saying constant injuries have taken away his love for the game.

Luck, who turns 30 on Sept. 12, had met with Colts owner Jim Irsay earlier to tell him of the decision.

The Colts played their third preseason game Saturday night in Indianapolis against the Chicago Bears. Luck already had been ruled out of the game because of an ankle injury, but he was seen on the sideline, laughing and conversing with teammates.

After the game, Luck announced his decision during an impromptu 25-minute news conference. He said an official announcement wasn't planned until Sunday afternoon, but he changed course once news broke during the game.

"I've been stuck in this process," Luck said, stopping several times to gather his emotions. "I haven't been able to live the life I want to live. It's taken the joy out of this game ... the only way forward for me is to remove myself from football.

"This is not an easy decision. It's the hardest decision of my life. But it is the right decision for me.''

Luck's early retirement ends what started as a promising career for the No. 1 overall pick in the 2012 draft, chosen to replace Peyton Manning. Luck led the Colts to the playoffs in each of his first three seasons in the NFL, including back-to-back AFC South titles and an appearance in the AFC Championship Game in 2014.

But his career took a bad turn when he suffered a shoulder injury in Week 3 of the 2015 season. He ended up missing 26 games -- including the entire 2017 season -- because of shoulder, kidney and rib injuries. It was during the 2017 season while out that Luck questioned whether he would be able to continue his career.

But Luck returned in a big way last season.

QBs Across NFL React to Luck News It was supposed to be just a regular Saturday night in the preseason. But then Andrew Luck announced his retirement, sending shock waves across the league. A look at how some of the QBs whose teams played Saturday night reacted to the news:

Deshaun Watson: "It was mind-blowing. It was something that of course caught everyone off guard. But, hey, he can control his own future. He's a great player. He's a great quarterback. One of the top five quarterbacks in the league. And he's doing it for the right reasons. For himself."

Drew Brees: "I think I'm probably like everybody else. A bit surprised and stunned, too. We heard it when we were on the sideline, actually -- somebody had gotten wind of it during the game. Listen, Andrew's a friend. I'll exchange text messages with him from time to time. So I'll be reaching out to him to check on him."

Russell Wilson: "I'm praying for him, praying that he stays encouraged. This game can take a toll on us physically but also emotionally, spiritually, everything else. I think that he's demonstrated class the whole time through everything. ... Being the No. 1 pick and everything else, there's a lot of pressure on him, and I think that he handled it with grace, and he handled it really well and had a tremendous career for how long he played."

Dak Prescott: "I mean helluva player, helluva player. Helluva guy the little bit I know of him being able to talk to him before a game and sharing a little bit of things. ... So respect his decision, wish him the best. Just know that he was one of my favorite players to watch around the league and learn little things from. Hate to see a great player like that leave the game, but like I said, don't know the details, don't want to speak on that. I'm not entitled to an opinion on that."

Patrick Mahomes: "Knowing Andrew, he's a great football player, but he's also a great human being. I haven't seen the full [scope] of the news, but I know he's going to make the right decision for himself and his family.''

He threw for 4,593 yards and 39 touchdowns to win NFL Comeback Player of the Year and lead the Colts back to the playoffs for the first time since the 2014 season, showing he remained one of the top quarterbacks in the league.

But an injury derailed Luck again earlier this year when he suffered a calf strain that kept him out of the team's offseason activities and minicamp. Luck took part in only three days of training camp -- none as a full participant -- before it was announced that he was shutting it down because he had difficulty moving in the pocket.

"I'm in pain; I'm still in pain," he said. "It's been four years of this pain, rehab cycle. 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.''

Luck told reporters Saturday night that he first started thinking about retirement two weeks ago, and general manager Chris Ballard said the sides started discussing the potential decision early last week.

"It was Monday," Ballard said. "We all sat down and had a talk and continued through the week. Emotional talks on our parts. Not any negative emotional talks. Just some real honest talks. But did not get a sense. I watched Andrew go through the shoulder, his routine and how he rehabbed and worked through things. He was going through the same process all the way from when he walked in the building. He came in Monday and started working through this."

It's stunning news for a Colts team that went to the second round of the playoffs last season and that, in the eyes of many, had a Super Bowl-caliber roster in 2019.

"It's very difficult," Luck said. "I love this team, I love my teammates."

Luck finishes his career with 2,000 completions, 3,290 attempts, 23,671 yards, 171 touchdowns and 83 interceptions. But some Colts fans seemed to forget those numbers, instead booing him as he walked off the field following Saturday's game.

"I'd be lying if I said I didn't hear it," Luck said of the boos. "Yeah, it hurt."

Now, the Colts will turn to Jacoby Brissett, the 26-year-old quarterback acquired from the New England Patriots in 2017.

With Luck dealing with a variety of injuries in 2017, Brissett started 15 games for Indy, throwing for 3,098 yards, with 13 touchdowns and seven interceptions. The Colts posted a 4-11 record in Brissett's 15 starts, and he ranked 27th out of 30 qualified quarterbacks with a 43.3 Total QBR and 30th out of 32 qualified QBs with a 58.8 completion percentage.

Andrew Luck by the Numbers 171: Career passing TDs, the most of any player not to play a game after his 30th birthday.

86: Number of games he played in the NFL out of a possible 112 (he missed 16 in 2017 due to shoulder; 1 in '16 due to concussion; 7 in '15 due to kidney; 2 in '15 due to shoulder)

39: TD passes last season, most by any QB in NFL history after not playing previous season

33: Wins in his first three seasons, tied for the second most by a QB in their first three seasons during the Super Bowl era (Russell Wilson 36; Dan Marino and Matt Ryan 33)

19.6: Average fantasy points since entering league in 2012, third-most PPG among QBs during that span

3: Luck's ranks in Colts' all-time history in pass yards (23,671), pass TDs (171), completions (2,000) and QB wins (53)

--ESPN Stats & Information

But Luck, Ballard, Irsay and coach Frank Reich all threw their support behind Brissett with the regular season two weeks away.

"We've got a good football team. This is a good football team," Ballard said. "We are young. We are good on both fronts. We have some good skill players. And a good young quarterback. We are not going to ask Jacoby Brissett to be Andrew Luck. Andrew Luck was a unique, unique player. But Jacoby Brissett is a winning football player in this league and, I think you heard what Andrew said, Jacoby Brissett is a rare, rare leader. He is. He's a rare human being, man. That locker room loves Jacoby Brissett."

Sportsbooks reacted quickly to the Luck news, taking the point spread on the Colts' Week 1 road game at the Chargers off the board and lengthening Indianapolis' odds to win the Super Bowl, the AFC and the AFC South.

The Colts had been four-point underdogs to the Chargers. Caesars Sportsbook moved Indianapolis' Super Bowl odds from 12-1 to 30-1, its AFC odds from 7-1 to 15-1, and its AFC South odds from -135 to +210.

But that mattered little to the Colts on a franchise-changing night.

"We have nothing but gratitude and thankfulness for the blood, sweat and tears he spilled as No. 12," Irsay said. "Part of our heart is broken tonight. We know we must go forward."

Information from ESPN's David Purdum and Adam Schefter was used in this report.