GREEN BAY – The list of reasons to bring back Tramon Williams was long.

The Packers had a shortage at the cornerback position, after other forays into free agency didn't work out. He's a veteran leader for an otherwise mostly young position group. He's played in a Mike Pettine defense, and he knows – and exemplifies – everything it means to be a Packer.

But however valid those items, they don't address what really matters most, to both the Packers and Williams.

"I don't think they would have just signed me if I couldn't play, you know?" Williams said in his first reunion with the Green Bay media on Tuesday, after three years elsewhere. "The first reason is because I can play still."

Williams is a marvel in that regard, a 35-year-old still going strong at a position not kind to players his age. Terence Newman just finished his 15th NFL season at age 39 for Minnesota, but he and Williams are exceptions that don't resemble the rule.

Having enjoyed a remarkably healthy career, in part due to the lengths he began going many years ago to take care of his body, Williams said he feels great and others have told him he "can do four or five more years, easy."

That's a discussion for another day, but in the here and now, Williams is back with the team that gave him a chance a dozen years ago, signing him to the practice squad late in the 2006 season when he didn't make Houston's roster as an undrafted rookie out of Louisiana Tech.

After two years in Cleveland and one in Arizona, Williams called it an easy decision to return to Green Bay, for all the reasons already mentioned. He's perhaps most excited about diving back into Pettine's playbook, which he characterized as full of change-ups that can keep offenses guessing.

"It's very aggressive, man," he said. "You have to be smart. It's simple but it's aggressive. There has to be a lot of smart guys on the field. Me being in that defense, I think I can guide some guys and teach some guys what they need to know in this defense. That's why I think the move made sense.

"They're going to recognize some things that they already know. But it's going to be a lot more things that you can adjust to keep the offense off-balance."

As for his new teammates in the secondary, a few are old acquaintances. His last year in Green Bay, 2014, safety Ha Ha Clinton-Dix and cornerback Demetri Goodson were rookies. Fellow corner Davon House was also here, and like Williams, he has returned after a couple years away.

"It means a lot," Clinton-Dix said of getting Williams back. "He's a guy I looked up to when I first came into this locker room. A true pro, a true leader. He's a guy who carries himself with a lot of energy."

For now, that energy will be directed to getting back to another Super Bowl.

Williams was instrumental in the Packers' run to the 2010 title, with his three interceptions in the first two postseason games going down in franchise lore. His leaping pick in the end zone in the final minute in Philadelphia sealed the wild-card win, and his pick-six on the final play of the first half in Atlanta six days later swung a back-and-forth game Green Bay's way.

His last play as a Packer is not how he should have gone out, so it's appropriate he's back. Russell Wilson's blitz-beating, perfectly placed pass to Jermaine Kearse for the overtime TD in the 2014 NFC title game was an opportunity the Seahawks shouldn't have had.

Now it's Williams with a new and rather unexpected opportunity, and the thoughtful, well-spoken veteran is out to seize it.

"Green and gold runs through my blood," he said. "To walk off the field on my last play as a Packer getting scored on to go to the Super Bowl, it was a tough way to end it. But God puts you in different situations. I ended up leaving and there was a reason why I left – for me to grow. I feel over these last three years, I've grown so much more than I would've probably ever done while I was here.

"Now, it's time for me to come back here and get things in order. I'm up for that challenge. I believe that we will be back in the Big Dance when it's all said and done. I'm hoping that these guys are here with me and we're going to get it done."