Aaron Williams made it perfectly clear Monday: He's back.
"I'm fully cleared to play," Williams said on the Bills' first day of voluntary spring practices. "Talked to all the coaches. Talked to all the training staff and the doctors. We really went and evaluated everything and made sure I was 100 percent before I got back out there."
So even though Monday's practice can barely be called that – it's more of a group workout put on by the team's strength-and-conditioning staff – Williams still said it felt "amazing" to be on the field.
"It's been so long since I've been with the team, actually," he said. "Been at home for the most part, but being back here, just working out with the guys, running with the guys, lifting with the guys, just feels right. Feels great."
Williams returned to practice near the end of the 2015 season, but has not played in a game since October, when he reinjured his neck in a game against Tennessee. The injury eventually required surgery, which Williams says was to "shave down" the C4 and C5 vertebrae in his neck.
Given the delicate nature of Williams' injury, there was a distinct possibility that Williams' playing career could have been over.
But he says that doubt is no longer in his mind.
"None at all," he said. "If I had any doubt, I wouldn't be playing. That was the one thing we talked about with my trainers. If there's any doubt possible, there's no reason for me to be out there. When you're out there on that field, you need to be 100-percent positive that you can play."
Williams referenced again Monday what he originally said at the end of last season: His only way of truly knowing whether his neck can withstand the rigors of an NFL collision is to actually go through one. The first chance for that won't come until players are in pads for training camp.
"That's the No. 1 test," he said. "I mean, we can do as many strength tests and as many mental tests as we can, but it's all going to come down to when we put the pads on.
That's "still a ways away, but my focus right now is to get in the best shape as I can, get my face in the playbook as much as possible, and then when that time does come and it's time to hit, then we'll worry about it."
Bills coach Rex Ryan doesn't sound like he's overly concerned about the possibility of Williams not being able to play.
"I'm very optimistic about it," Ryan said of getting Williams back. "Aaron's ready to go, guys. We feel confident in it. ... I don't think he'll truly be 100 percent or be the Aaron Williams we know until he hits somebody. That's what's missing right now.
"We know he's ready, but he's still got to get over that first contact. I feel very confident he'll be ready."
Williams admitted Monday that his approach has been changed based on what he's gone through. After his surgery, he wasn't able to move his neck for three weeks.
"I'm not going to push myself to the limit where if I feel like I'm hurting, I should keep playing just because I feel like I need to be out there," he said. "If my body is not capable of being out there at 100 percent, even the slightest little injury, I'm going to remove myself from the situation, get evaluated, and if they feel like I'm better and capable of going back out on the field, then I'll go back out there."
Williams admitted coming back into the game against Tennessee was a mistake.
"At that time, I was young and just trying to prove something," he said. "Prove that I'm strong and that nothing can really phase me, but at the end of the day I've got to look at my health."