Andrew Miller, who spent his winter as one of the players' union's top representatives in helping negotiate a new collective bargaining agreement with the owners, announced his retirement from the major leagues after 16 seasons. The St. Louis Post-Dispatch first reported the news and ESPN's Jesse Rogers has confirmed it.

The 36-year-old reliever and two-time All-Star spent the past three seasons with the Cardinals and was a free agent. He appeared in 40 games in 2021 with a 4.75 ERA over 36 innings.

The sixth overall pick by the Tigers in 2006 out of the University of North Carolina, Miller and Cameron Maybin were the top prospects acquired when the Marlins traded Miguel Cabrera to Detroit after the 2007 season. The 6-foot-7 left-hander struggled as a starter with the Marlins and was viewed as a failed top prospect but eventually emerged as a reliever with the Red Sox and Orioles before signing a lucrative free-agent contract with the Yankees in 2015.

He saved 36 games that year but was traded to Cleveland in 2016, where he made his biggest impact during a two-year run during which he was arguably the game's top relief pitcher. He helped the Indians reach the World Series in 2016 with one of the best postseason stretches ever seen from a reliever. With manager Terry Francona using him for multiple-inning stints at any time in the game, he pitched four scoreless innings against the Red Sox in the division series and then took home ALCS MVP honors, appearing in four of the five games against the Blue Jays and allowing no runs with 14 strikeouts in 7.2 innings. Miller and Cincinnati's Rob Dibble in 1990 are the only non-closers to win a postseason MVP award.

Miller picked up a hold and a win as Cleveland took the early lead over the Cubs in the World Series, but the Cubs finally got to him in Game 7 when they scored two runs off him, including a David Ross home run. Still, Miller finished that postseason with 30 strikeouts in 19.1 innings, postseason records for a reliever for innings and strikeouts. Miller made his second straight All-Star Game in 2017 as Cleveland returned to the postseason. Over the 2016 and 2017 seasons, he went 14-4 with 14 saves and a 1.45 ERA, striking out 218 batters in 137 innings thanks to an explosive fastball and wipeout slider.

"Playoff baseball is the greatest place to be and there is no better feeling in the world than having success on that stage," Miller wrote in a text this week to the Post-Dispatch's Derrick Gould. "I feel very fortunate that my career worked out the way that it did."

He wasn't as dominant after that two-year run and had trouble staying healthy.

"I'm old," he told The Athletic's Peter Gammons in March after the new labor deal was struck.

Known as one of the smartest and most affable players in the game, Miller had first been a union rep while with the Marlins. He and Max Scherzer were the two players leading the talks -- although Miller, Scherzer and the six other players on the executive subcommittee actually voted unanimously against the agreement. (Player representatives from each team voted 26-4 to approve the offer.)

When the negotiations were still going on, Miller told ESPN's Rogers that talks definitely got heated.

"It can get hot because we're passionate about this. I'm passionate about finding a way to address the issues, and I'm passionate about the sport," he said. "If that means someone raises their voice or uses a word that is four letters long, so be it. But ultimately we're meeting, we're talking. Some times it's prettier than others."