When the Jets squandered a chance to clinch the playoffs during the final game of the 2015 season, rookie Leonard Williams assumed that he would get another chance soon.

The maybe-next-year hopes kept mounting, but the eighth-year defensive tackle is finally headed to the playoffs after the Giants’ victory over the Colts last week.

“That feeling after the game was just unbeatable,” Williams said. “Just seeing all the smiles on my teammates, just knowing how long it’s been since I’ve had an opportunity to do this, it means a lot to me.”

Williams shared the story of the Jets’ missed opportunity with other defensive linemen last week.

“I was like, ‘After that game, being a rookie and going that far, I was thinking ‘If we came this far, why not again next year?’ ” Williams said. “The fact that it took seven years to get back there is crazy. I was trying to let everyone know the meaning of these opportunities don’t come often and that we should take advantage of it. We did. We went out there and played one of our best games as a team.”

Williams isn’t practicing this week due to a neck injury and is unlikely to play Sunday against the Eagles as he rests up to face either the Vikings or 49ers in the first round.

“It’s something that really isn’t going to get better until I’m not playing football … during the offseason,” Williams said. “I’m taking care of it as much as possible during the week, the team is doing a good job of taking care of me. It’s all been worth it. The pain, I’ve been dealing with it and playing. It’s paid off the fact that we have a playoff spot.”

Defensive coordinator Wink Martindale said that no Giants have expressed any reservations about tackling in the aftermath of Bills safety Damar Hamlin’s life-threatening injury because of the understanding that the “chance of something like that happening is getting struck by lightning.”

“It was a tough thing because I think it’s human nature to put yourself [in those shoes], ‘What if that’s one of your guys?’ ” Martindale said. “How they reacted to the entire situation, I thought, was spot on. The medical staff and all that, to me, that builds confidence in our league.”

Martindale said players know “our defensive meeting room is a safe place. We talk about anything.”

Asked about Kayvon Thibodeaux’s controversial sack celebration Sunday against the Colts, Martindale first floated the company line of “we’re moving on to Philly.” Martindale then proceeded to defend his rookie outside linebacker against criticism fueled when Colts head coach Jeff Saturday called it “tasteless” and “trash.”

“He did not know the quarterback was hurt,” Martindale said. “He’s a good guy, and he did not know [Nick Foles] was hurt.”

Martindale said it was a “dangerous” play with two free runners coming off the edge, zeroing in on the backside of the quarterback, but he reiterated that if Thibodeaux had known Foles was hurt, he wouldn’t have pantomimed making a snow angel on the ground afterward.

“To me, it doesn’t look as bad as what everybody’s trying to blow this thing up as,” Martindale said. “I know the guy. I know the person. I know his heart.”

Hall of Fame pass rusher Michael Strahan was a guest at practice Thursday and spent time talking with defensive players — including a one-on-one with Thibodeaux. The 15-year Giants star also spoke with head coach Brian Daboll and general manager Joe Schoen off to the side.

C Jon Feliciano (back) was upgraded Thursday to a limited practice participant. DT Dexter Lawrence was back after taking Wednesday’s practice off for workload management. CB Adoree’ Jackson (knee) was limited. OLB Azeez Ojulari (ankle) did not practice.