The Patriots' Rob Gronkowski announced his retirement Sunday via Instagram. (Jeff Roberson/Associated Press)

PHOENIX — Rob Gronkowski, the endearingly fun-loving and ceaselessly productive tight end who helped the New England Patriots to three Super Bowl titles and became one of the greatest players ever at his position, walked away from football Sunday, announcing his retirement at age 29.

“It all started at 20 years old on stage at the NFL draft when my dream came true, and now here I am about to turn 30 in a few months with a decision I feel is the biggest of my life so far,” Gronkowski wrote on Instagram. “I will be retiring from the game of football today.”

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It all started at 20 years old on stage at the NFL draft when my dream came true, and now here I am about to turn 30 in a few months with a decision I feel is the biggest of my life so far. I will be retiring from the game of football today. I am so grateful for the opportunity that Mr. Kraft and Coach Belichick gave to me when drafting my silliness in 2010. My life experiences over the last 9 years have been amazing both on and off the field. The people I have meet, the relationships I have built, the championships I have been apart of, I just want to thank the whole New England Patriots organization for every opportunity I have been giving and learning the great values of life that I can apply to mine. Thank you to all of Pats Nation around the world for the incredible support since I have been apart of this 1st class organization. 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. It was truly an incredible honor to play for such a great established organization and able to come in to continue and contribute to keep building success. To all my current and past teammates, thank you for making each team every year special to be apart of. I will truly miss you guys. Cheers to all who have been part of this journey, cheers to the past for the incredible memories, and a HUGE cheers to the uncertain of whats next.

A post shared by Rob Gronkowski (@gronk) on

Gronkowski dealt with injuries throughout his career, and his decision was not a surprise. He had publicly considered retirement last offseason before returning, and he said following the Patriots’ Super Bowl triumph over the Los Angeles Rams in February that he again would contemplate his football future in subsequent weeks.

The announcement came with Patriots officials, including team owner Robert Kraft and Coach Bill Belichick, gathered at a Phoenix resort for the annual league meeting.

“I am so grateful for the opportunity that Mr. Kraft and Coach Belichick gave to me when drafting my silliness in 2010,” Gronkowski wrote. “My life experiences over the last 9 years have been amazing both on and off the field. The people I have [met], the relationships I have built, the championships I have been a part of, I just want to thank the whole New England Patriots organization for every opportunity I have been [given]. ... 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.”

Gronkowski was a longtime favorite target of quarterback Tom Brady. He was a matchup nightmare for opposing defenses, and he was a ferocious blocker whose talent and success are almost certain to land him a spot in the Pro Football Hall of Fame.

He finishes with 521 catches for 7,861 yards and 79 touchdowns over nine seasons, all with the Patriots, but his body betrayed him at times. He played all 16 regular season games only twice — in his first two seasons. He was selected to five Pro Bowls and was named all-pro four times.

“In the nine years that I have known Rob Gronkowski, I have never known him to have a bad day,” Kraft said in a statement issued by the Patriots. “He always has a youthful exuberance about him and is a joy to be around. As a player, he earned the respect of his coaches and teammates for his hard work, preparation, selfless attitude and the sheer dominance of his game."

His reputation for partying as zealously as he played and his playful nature made him, in some ways, the anti-Patriot — the lovable antithesis to the ruthless competitiveness of Belichick and Brady. But he was respected by members of the organization for his hard work and willingness to play through pain.

Gronkowski’s retirement leaves a void as Brady plays on and the Patriots seek to add more Super Bowl titles to their collection.

“It was a pleasure and a privilege to coach Rob Gronkowski the past nine years,” Belichick said in a statement. “From his rookie year until his final season and through countless times in between, Rob was a major reason why we won games and championships. His elite combination of size, skill, intelligence, toughness and ability to perform in pressure situations set him apart.”

Gronkowski is said to have been prudent about saving his income from football and living off his endorsement earnings. There has been speculation that he could take up an acting career as part of his post-football life.