Rob Gronkowski undergoes back surgery; timetable for return unknown
The operation performed by Dr. Robert Watkins was successful, said Drew Rosenhaus, Gronkowski's agent.
On May 20, the Patriots star had his fourth surgery on the left forearm that he broke on Nov. 18 while blocking for an extra point in a 59-24 win over the Indianapolis Colts. He broke it again in the Patriots' first playoff game, a 41-28 win over the Houston Texans. Rosenhaus said the fourth surgery was expected to be the last on his forearm.
The Patriots open training camp in late July and start the regular season on Sept. 8 at Buffalo.
In 43 NFL games, Gronkowski has scored 39 touchdowns, 38 on passes and one on a run.
Drafted in the second round out of Arizona State in 2010, he was chosen for the Pro Bowl in 2011. In that season, he set NFL records for tight ends with 17 touchdown catches, 18 total touchdowns and 1,327 yards receiving.
In 11 games last season, Gronkowski had 55 catches for 790 yards and 11 touchdowns. He missed five regular-season games with forearm and hip injuries and the AFC championship game, a 28-13 loss to the Baltimore Ravens, after he re-broke his forearm.