It's a sad day to be a New England Patriots fan as Rob Gronkowski announced that he is retiring from the NFL at the age of 29. In just nine years, Gronk was able to help the Patriots win three Super Bowl titles, cementing his legacy as one of the best tight ends to ever play the game. Having suffered a plethora of injuries throughout his career, retirement was inevitable although not everyone believed it would happen so soon. 

Gronkowski's quarterback, the legendary Tom Brady, took to Instagram to congratulate the tight end on his career, while also reflecting on their time together as teammates.

Per @tombrady:

"What an honor and privilege to play with you these past nine years @gronk! You accomplished so much and our team was almost unbeatable when you were on the field! Your fun-loving, inspiring, and positive energy made an impact on everybody you came into contact with! Not just that, but for as great as a player you are, you are a better teammate and person. The NFL was a better place with you in it! But I have no doubt you will be a success in anything you do!!! Love you pal!"

Gronkowski announced his retirement via Instagram, saying: "Thank you for everyone accepting who I am and the dedication I have put into my work to be the best player I could be. But now its time to move forward and move forward with a big smile knowing that the New England Patriots Organization, Pats Nation, and all my fans will be truly a big part of my heart for rest of my life."

The 29-year-old tight end will be going out on top as the Patriots won the Super Bowl this past season.