12:44 PM PT -- Tom Brady just weighed in on his BFF's retirement ... writing in a sweet note on Gronk's Instagram page, "Love you as a man, teammate and friend. One of a kind in every way❤️"
He later added in a lengthier post on his own IG page, "Having Gronk in your locker room was every NFL players dream. I'm proud of all that we've accomplished together, and even more excited for all you have ahead of you.
The Buccaneers also wished Gronk a goodbye in a statement Tuesday afternoon, calling the tight end "a true professional who left it all on the field for us the past two seasons and helped establish a championship culture in our building."
Rob Gronkowski is once again hanging up his cleats ... the legendary tight end has just retired from football for the second time in his career.
The Tampa Bay star announced the news Tuesday ... this after he initially came out of retirement to play with Tom Brady and the Bucs in 2020.
In his two seasons with TB12 in Florida since, he won another Super Bowl ring ... and caught 100 more passes for 1,425 yards and 13 TDs.
"I want to thank the whole entire first class Buccaneers organization for an amazing ride, trusting me to come back to play and help build a championship team," Gronk said in a lengthy retirement post on his Instagram page.
"I will now be going back into my retirement home, walking away from football again with my head held high knowing I gave it everything I had, good or bad, every time I stepped out on the field."
Gronk first called it quits following the 2018 season ... saying after a 9-year stint with Brady and the New England Patriots, his body didn't feel well enough to keep going.
Gronk had toyed with the idea of coming back for a third season in Tampa Bay this offseason, telling TMZ Sports he was staying "in shape" just in case he got the itch to play again. But, apparently, that itch never came ... and he seemed sure of his decision in his announcement Tuesday.
"From retirement, back to football and winning another championship and now back to chilling out," Gronk said, "thank you to all."
What's interesting ... Gronk's agent, Drew Rosenhaus, said there is at least a small chance this isn't the end of Rob's historic career ... telling ESPN's Adam Schefter, "It would not surprise me if Tom Brady calls him during the season to come back and Rob answers the call. This is just my opinion but I wouldn't be surprised if Rob comes back during the season or next season."
But, for now, it seems the 33-year-old is really done.
See ya in five years in Canton!
Originally Published -- 11:30 AM PT