The Giants' third-year fullback passed his physical and began working out Thursday.
"It feels good," Hynoski said. "I'm very happy to be out here with my teammates and just get out here moving around and doing some things."
Despite being activated off the PUP list, Hynoski did not get any team reps in practice Thursday. He won't play Saturday night against the Jets and doubts he'll play in the final preseason game five days later against the Patriots, but thinks he could be ready for Week 1 of the regular season.
"I'm hoping for it," Hynoski said. "That's my goal, but if it takes to Week 2 or 3, that's fine.
"We have a very smart medical staff and trainers, and they're going to put me in the right position when they know I'm physically fit to be out there and performing at the best that I can."
Hynoski has been sidelined since May 24 after undergoing surgery to repair his MCL and a chip fracture to the lateral plateau of his left knee. He suffered the injury during organized team activities.
Hynoski is a key piece of the running game for the Giants, who have been using tight end/H-back Bear Pascoe at fullback in his absence. Backup tight end Larry Donnell saw some snaps as a backup fullback in the preseason opener.
Giants coach Tom Coughlin acknowledged that Hynoski is an important part of the Giants' offense.
"There aren't many (fullbacks) around," Coughlin said. "Even today, when you look around in the league, there are not many guys that are 265 (pounds) and have the skill set that Henry has."
The Giants also added rookie tackle Austin Holtz to the 90-man roster Thursday.
ESPNNewYork.com's Kieran Darcy contributed to this report.