Kerry Collins said Monday he's "99 percent sure" that he will retire for a second time. "When you start dealing with concussions at my age and this point in my career, I'm inclined to think this is going to be it for me," Collins said. Collins, 38, was placed on injured reserve last week, ending his season. He never fully recovered from a concussion suffered in a Sept. 25 loss to the Steelers. "I just didn't respond the way everybody had hoped," Collins said. "It just took longer. Some symptoms just lingered. There was concern that since it did take so long, in the future there would be a real possibility of longer-term damage. "(Concussions) hadn't been a big part of my career, but this one was significant."