Hynoski underwent an MRI, which revealed an injury to his medial collateral ligament and a chip fracture to the lateral plateau, the Giants said. Dr. Russell Warren will perform the surgery at The Hospital for Special Surgery.
Hynoski said his goal is to return to the field for the season opener on Sept. 8 at Dallas. It is not clear how much of the offseason he will be out.
"I am going to set my mind to being ready for the first game of the regular season," Hynoski said in a statement released by the team. "They said that is not an unrealistic goal, and I will do everything in my power to be ready for the start of the season."
Hynoski suffered the injury on a play behind the line of scrimmage. The 6-foot-1, 266-pound blocking fullback has become a valuable part of the Giants' running game. Tight end Bear Pascoe could play fullback with Hynoski out, but the team also could look to sign a fullback for training camp in July.