Leonhard was injured during the first half of the Jets 37-10 win over the Chiefs at MetLife Stadium on Sunday when he intercepted a pass by Tyler Palko intended for Steve Breaston, and the Kansas City wide receiver grabbed Leonhard's leg for the tackle. Leonhard went down and immediately grabbed at his leg and needed help from two trainers to walk off the field before being carted from the sideline to the locker room.
It is the second straight year that Leonhard will not be available for a late-season playoff push. Last year he broke his right leg.
"You feel absolutely terrible for him, knowing how he overcome that last injury and what that meant," Ryan said. "This team means everything to Jim and his leadership is obviously going to be missed, without question. He's one of the guys that just elevated other players around him. Everybody respects Jim, and he is definitely going to be missed. But I know Jim. I think he'll get the surgery, whenever that is he'll get it, and I'm sure be around the building and be part of us anyway. He just can't do it physically."
Ryan said Leonhard will need surgery to repair this injury and that general manager Mike Tannenbaum will look to shore up his position via free agency. Brodney Pool and Eric Smith are locked in as starters at safety. Last season Pool took over for Leonhard.
"Brodney did a tremendous job as the season went on so we're definitely in his capable hands to fill in for Jimmy," Ryan said.
Leonhard had also recently reassumed the primary punt return duties, which will now go back to rookie Jeremy Kerley. The 29-year-old safety finished with 60 tackles and an interception this season.
Leonhard is an unrestricted free agent at the end of this season. Ryan said he expected Leonhard to rehab the injury at the Jets Florham Park training facility and serve as an unofficial extra coach when he can.
"This is not going to be the end for Jim Leonhard, I think this is a setback,"said Ryan, who brought Leonhard from Baltimore when he was named the Jets head coach three years ago. "...I don't think Jim Leonhard's done playing."
"He's in good spirits right now waiting for the swelling to go down so he can have the surgery," Cromartie said.
Ryan and each of his players noted that Leonhard's injury might be difficult, but the Jets have Philadelphia on the schedule and can't pause in preparation. Instead, defensive schemes will have to be tweaked to accommodate new personnel, and backups moved into new roles.
"It's a huge blow to our football team but it's one that we think we can overcome," Ryan said.
Jane McManus is a reporter and columnist for ESPNNewYork.com. Information from The Associated Press was used in this report.