TAMPA, Fla. -- In a shocking move, Buccaneers Pro Bowl left guard Ali Marpet is retiring, he announced on Instagram.

Marpet is just 28 years old and finished off his first Pro Bowl season. He is considered arguably one of the top -- if not the top -- Buccaneers offensive linemen.

A source told ESPN that Marpet made the decision due to concerns for his overall health.

"After seven formidable years with the Tampa Bay Buccaneers, I've come to the decision to retire from the game that has given me so much," he wrote in his post. "This organization and the people surrounding it have helped not only fulfill a dream, but also helped build me into the person I am today. I've made Tampa Bay my home and I look forward to serving this community in the coming years. To the coaches and teammates, family and friends, an Instagram post simply can't express the profound impact you've had on me. I'm eternally grateful. Thank you Tampa Bay."

A second-round draft pick out of Hobart College in 2015, Marpet became the highest-drafted player (61st overall) in Division III history. He also became the first Division III player selected in the top 100 of the draft since 1990.

"It has been one of my greatest professional thrills to see his rapid ascension from a small college standout into one [of] the NFL's best all around offensive linemen," Buccaneers general manager Jason Licht said in a statement.

The Bucs already face the daunting challenge of replacing future Hall of Fame quarterback Tom Brady. Filling the void left by Marpet, who missed just 12 games in seven seasons, will be another big challenge.

Marpet was due to make $10 million in 2022.

"I can't say enough about what Ali has meant to our team over the three seasons since my arrival. He has been the consummate professional and has been a rock for us in the interior of our offensive line," Buccaneers coach Bruce Arians said in a statement. "We will miss him on the field and in the locker room, but I am happy that he gets to go out as a Super Bowl champion and Pro Bowler. It is never easy saying goodbye to a player who has meant so much to our success, but I support and respect his decision and wish him a great life after football."

Marpet has served on the Bucs' social justice advisory board and last summer met with Vice President Kamala Harris during the team's visit to the White House to discuss voting rights.

In his statement, Licht lauded Marpet for providing "the vision and passion that was crucial" to the Buccaneers' social justice advisory board's "launch and ongoing work."

From 2018 to 2021, Marpet registered a 93.7% pass block win rate, which ranked ninth in the league among guards, according to ESPN Stats & Information research. He became one of just six players to post a pass block win rate of 92% or higher at guard in each of the past four seasons, joining Quenton Nelson, Zack Martin, Joel Bitonio, Brandon Scherff and Andrew Norwell.

Marpet's most memorable play, arguably, was pulling to the outside on Leonard Fournette's 27-yard touchdown run in Super Bowl LV, which the Bucs won 31-9 over the Kansas City Chiefs.

Current and former Buccaneers teammates showered Marpet with praise in the comments of his Instagram post.

• "Congratulations, you are a warrior," Brady posted. "It was an honor!!"

• Best friend and left tackle Donovan Smith wrote, "Love you my guy," along with an emoji with tears and a heart.

• "Was an honor brother! Enjoy retirement," center Ryan Jensen posted.

• Inside linebacker Lavonte David wrote: "Was definitely an honor to be in your presence daily my Guy! Enjoy retirement!"

• "Love you bro happy retirement Champ," wide receiver Mike Evans wrote.

"I think he accomplished his goals, values his health, is looking for more challenges. Ali has a very strong inner voice, and he is courageous enough to follow it. I'm in awe," Marpet's father, Bill, told ESPN.

In addition to Brady's and Marpet's departures, Jensen, also a Pro Bowler, and right guard Alex Cappa, a Pro Bowl alternate, are set to become unrestricted free agents next month.