Patriots tight end Rob Gronkowski announces retirement

Patriots tight end Rob Gronkowski says he is retiring from the NFL after nine seasons.

Gronkowski announced his decision via a post on Instagram Sunday, saying that a few months shy of his 30th birthday "it's time to move forward and move forward with a big smile."

"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 in his post. "I will be retiring from the game of football today."

Gronkowski's agent, Drew Rosenhaus confirmed his client's decision to retire.

The tight end, who turns 30 in May, leaves as a three-time Super Bowl champion who has established himself as one of the most dominant players at his position.

But he has been dogged in recent seasons by back, knee, ankle and arm injuries that have limited his ability to stay on the field.

More details to follow.