"He doesn't have limits that I know of," Patriots coach Bill Belichick said Thursday of Gronkowski, who saw his 2016 season cut short due to a back injury that required surgery.
Belichick dismissed any difference in the 28-year-old Gronkowski's approach following the injury.
"I mean, that was all pretty much over with by the start of the offseason program," Belichick said. "So, he's been trying to keep up with everybody else. We'll see how it goes."
Gronkowski gave the fans a thrill on Thursday after unleashing his signature spike following a touchdown reception.
The 6-foot-6, 265-pounder was injured in Week 12 against the New York Jets on Nov. 27. He caught 25 passes for 540 yards and three touchdowns in eight games in 2016.
Gronkowski, a four-time Pro Bowler, hasn't played all 16 regular-season games since 2011. He has played in 11 or fewer games in three of the past five seasons.
In seven NFL seasons, Gronkowski has 405 receptions for 6,095 yards and 68 touchdowns.