After Indianapolis Colts’ quarterback Andrew Luck shocked the entire world of sports by retiring during this season’s preseason slate, sports everywhere have been wondering what players may follow suit. While the sport of baseball is much, much less of a physical attack on an athlete’s body than that of football, baseball still can take its toll on a human’s body.

With that in mind, this article will detail a list of five of the most shocking retirements across all of MLB history. The shocking areas of each situation differ from player to player, but the fact that they all surprised a lot of people by departing from the game that they gave so much to is what gives them a spot on this list.

Old and new players alike, this list will open your eyes to situations with professional athletes that not a lot of people may be familiar with. By showing these details, hopefully, we as fans can garner a better appreciation for what athletes do and how it ultimately all takes a toll on the athletes, whether we can see it or not.

Lou Gehrig – New York Yankees

Retirement Date: June 21, 1939
Retirement Age: 36

Yet another MLB player who ultimately retired in his 30s, Henry Louis Gehrig, more notably known as Lou Gehrig, was unfortunately forced to step away from the game. His diagnosis of ALS, which became named after Gehrig later on down the road, stripped Gehrig of his ability to suit up in a Yankees uniform after his 16+ season career.

Gehrig was one of the best first basemen that helped revolutionize the game, and his legacy as being one of the best offensive players all-time will always be there for reference. In 1937, Gehrig managed to rank between the best and the fourth-best in the American League across eight different offensive categories, a testament to the type of legacy that Gehrig would have.

Taken from us less than two years after he retired, Gehrig’s bout with ALS was a very hard one to watch, especially with how highly thought of he was. Regardless of the disease that was slowly tearing him away, he was consistently thought of by his peers in very high regard, and his legacy both as an MLB player and as someone who was dealt a tough hand during a stretch of his life will live on in lore forever.

Sandy Koufax – Los Angeles Dodgers

Retirement Date: November 18, 1966
Retirement Age: 30

Even after he had just won his second consecutive Cy Young Award, Los Angeles Dodgers starting pitcher and legend Sandy Koufax hung up his cleats while only being 30 years young. Having surprised even his fellow pitcher Don Drysdale with the decision, Koufax valued his personal health over athletic accomplishments every day of the week and even twice on Sundays.

Koufax, who did not wish to continue his professional playing days due to a fear for permanent damage to his left (pitching arm) elbow that was already dealing with arthritis, left the Dodgers at the peak of his abilities. Putting up a 27-9 record with a 1.73 ERA in 1966, Koufax was thought to have given up too early on his playing career, but the only opinion in that conversion was the one of the player who was giving up playing a kid’s game.

Koufax will forever go down as one of the best pitchers in the history of the Dodgers and in the MLB, as the lefty pitched in the major leagues since his age-19 season. Having become one of the first two pitchers to earn over $100,00 in a season after holding out with Drysdale, Koufax actually put together one of his best seasons in his career in his final year, even after he did not think that he would be able to make it through the 1966 season due to the health of his arm.

Dave Nilsson – Milwaukee Brewers

Last Game: October 3, 1999
Retirement Age: 30

One of the more unexpected retirement stories for an MLB player, former catcher Dave Nilsson retired from the MLB after his best career season in 1999, to go and… play baseball in his homeland of Australia. Not citing a health or any other common reasons, Nilsson put together his best season as a professional player for the Milwaukee Brewers, left a ton of potential money on the table from other teams, and went back to Australia to enjoy playing the sport of baseball.

His loyalty to his country was evident throughout his entire career, as the Brewers (at times) played second fiddle to the teams that Nilsson was a part of back in Australia. Nilsson’s eight years in the MLB were relatively uneventful, although he was a National League All-Star in 1999 and was even the first-ever Australian to play in the Mid-Summer Classic.

Nilsson was with the Brew Crew through their transition from the AL to the NL, and he saw time as the team’s catcher, first baseman and even was an outfielder from time to time. Not truly viewed as a utility player, Nilsson was mostly a catcher by trade, and his career in a Milwaukee uniform will be remembered for his offense, especially when he became the first Brewer to hit two home runs in the same inning, coming against the Minnesota Twins on May 17, 1996.

Ken Griffey Jr. – Seattle Mariners

Retirement Date: June 2, 2010
Retirement Age: 40

One of the saddest retirement processes made by a player that was caused by a steep downtick in performance, Ken Griffey Jr.’s return to Seattle was awesome in its first year, but the second year was far from the year prior. In 2010, Griffey Jr. unceremoniously left the team during the middle of a series, drove to Florida and submitted his immediate retirement to the front office at that point, putting an end to what had been a tumultuous final chapter to Griffey Jr.’s career.

Having played with his dad, Ken Griffey Sr., while in Seattle the first time, the Mariners and Griffey Jr. always had that bond together, something that held strong and true even with how his career ended. Both Junior and Senior became the first father-son duo to wear the same uniform and be on the field at the same time on Aug. 31, 1990, for the Mariners, which is a hell of an accomplishment in itself.

Having gone to play for the Cincinnati Reds and the Chicago White Sox in between his two stints as a member of the Mariners, Griffey Jr. came home for his final two seasons, even though that final season was running amuck with controversy. He will go down as one of the best personalities in the game, as he always had a huge smile on his face, enjoyed playing the game of baseball and was not afraid to let others know.

Alex Rodriguez – New York Yankees

Retirement Date: August 12, 2016
Retirement Age: 40

As are most things with the New York Yankees, things do not always go over as smoothly as they are desired – just ask Alex Rodriguez. The long-time member of the Seattle Mariners, Texas Rangers, and the Yankees was essentially forced out of the Bronx to pave the way for younger prospects to come up and produce.

For A-Rod, his up-and-down career was filled with steroid talk, juicing and the dominant offensive performances that he produced over the years. His 22-year career had a lot of positives in it too, but ultimately it was overshadowed by the negative aspects that will always be attached to his play.

Oh, and those two prospects that were referenced earlier? Yeah, they just happened to be catcher Gary Sanchez and outfielder and slugger Aaron Judge, in case you are keeping track at home.

As tumultuous as his career was, Rodriguez will still have his name plastered all over the record books for his accomplishments, and his departure (or forcible removal) from the MLB is something that will always be on the minds of Yankee fans everywhere.