The star tight end for the New England Patriots participated in drills with his teammates during the 15 minutes reporters were allowed to observe the start of practice.
Gronkowski isn't expected to play in the first few games but wasn't placed on the physically unable to perform list, a move that would have required him to miss at least the first six games of the season.
"He looked good," tight end Michael Hoomanawanui. "He looked almost Gronk-esque."
In his three NFL seasons, Gronkowski has been chosen for two Super Bowls and caught 187 passes for 38 touchdowns despite missing the last five regular-season games last year.
He's had four operations this year, three on his broken left forearm and one on his back on June 18. He had another forearm surgery last year after breaking it on Nov. 18 while blocking on an extra point against the Indianapolis Colts.
Gronkowski walked into the locker room with a smile Sunday and told reporters he would speak with them later in the week. The other two tight ends were glad to see him working out in pads. During training camp, he frequently watched practice from the sideline while dressed in a T-shirt and shorts.
"It was very cool to see him out there" on Sunday, said tight end Zach Sudfeld, who made the team as a rookie free agent from Nevada. "This is the first time I've been able to practice and have him be out there, so it was a great experience."
The cheerful Gronkowski has attended team and positional meetings and watched film, so he hasn't been a stranger to his teammates.
Practicing with him, though, provided "a little sense of normality," Hoomanawanui said, "It's definitely great to have him out there back with the team even though we see him each and every day in every meeting. We're used to that, but just to have him out there—Gronk being Gronk—kind of lifts everyone's spirits, helps the team out."
Last year's other star tight end, Aaron Hernandez, is being held without bail on a murder charge. The Patriots released veteran tight ends Jake Ballard and Daniel Fells on Saturday.
That left just Gronkowski, Hoomanawanui and Sudfeld as tight end on the roster.
Sudfeld was expected to make the team after a strong preseason but was thrilled to get the official word on Saturday.
"I was very excited, obviously," he said. "It's kind of a childhood dream come true to make the team in the NFL. But, at this point, I'm trying to look forward because there's a lot of work that has to be done. ... Now the real work begins."
At 6-feet-7 and 260 pounds, Sudfeld is about the same size as Gronkowski.
"He's been teaching me a lot," Sudfeld said. "Just for him to be able to show me the ropes a little bit has been really good."
Hoomanawanui is three inches shorter than Sudfeld and has greater versatility, sometimes lining up in the backfield. He played 14 games for the Patriots last year after being released by the St. Louis Rams on the final mandatory cut. He has 25 catches in 30 NFL games.
He took a pay cut this year to stay with the Patriots.
"It's tough going from team to team. I've done that once before, last year, and the learning curve is tough," he said. "Usually, the guys that pick up on it are the guys that'll stick around. ... Being able to come back here in the offseason, in the spring, in training camp, definitely helped my cause."
So did his ability to fill different roles.
"Since I got here that has always been my (goal), to do whatever it is that (coach Bill Belichick) needs me to do to help them win," he said. "I think coaches have noticed that and I've taken it to heart and really worked on that. So that's why I'm still here."
He's here practicing, again, with Gronkowski.
"He's the same each and every day," Hoomanawanui said. "There's really no highs and lows with him, no matter the situation, and I think that's maybe the greatest characteristic of all. He's obviously a great football player, but things he brings to the meetings and the team each and every day are pretty special, too."
AP NFL website: www.pro32.ap.org