ENGLEWOOD, Colo. -- They don't really know how or why, and at this point Brandon McManus and Von Miller don't really care, but the Denver Broncos kicker and Pro Bowl pass-rusher have formed the kind of friendship that lasts a lifetime.

It may seem odd that McManus, a kicking ace and Philadelphia-area native, and Miller, the team's megawatt star and self-professed "chicken farmer" from Texas, have become so close, but they can't imagine the future without each other. And Monday, the Broncos' BFFs get to spend Christmas Eve together.

"I just picture us with gray hair, out of shape, sitting on the porch somewhere, watching our grandkids play, you know?" Miller said. "That's just B-Mac and I. I can't even really remember like the official start of it or anything, but now we have that bond, his family, my family."

"I think when some people look at it, there's the star of the NFL that Von is, over here," McManus said. "And then there's the kicker, sometimes the hero and sometimes the scapegoat, but he's the kicker. But you know my wife, my dad, everybody in my family, Von is a part of it. Just friends forever."

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So much so that as McManus and his wife prepare for the birth of twin boys in January, the couple has tabbed Miller with something else to add to his personal to-do list.

"Since he was the second player drafted [in 2011], we told him he could be the godfather of the second boy," McManus said with a laugh. "My brother-in-law and sister are going to be the godparents for the other, so we're all set. But Von is super-pumped about that, I mean super-pumped, we may have to rein him in some."

Miller traces their friendship to 2014. Miller was in the midst of a vocational rebirth after opening the 2013 season with a six-game suspension for violating the league's substance abuse policy and closing the season with a torn ACL that forced him to miss Super Bowl XLVIII, a 35-point loss to the Seattle Seahawks.

McManus went undrafted in 2013 and was essentially a rookie in 2014 going through a kicker's often-bumpy first-year NFL ride. McManus had already been waived by the Indianapolis Colts, traded (to the Broncos) by the New York Giants and waived by the Broncos before he was signed back to the roster in December of that season.

McManus missed four of 13 kicks that year and didn't always project as the second-most accurate kicker in franchise history, a title he now holds. McManus had ice in his veins during the team's playoff run to Super Bowl 50, going 10-for-10 in the postseason.

"I think when I first got here I just respected how he worked, how he did things coming back from his injury, the off-the-field things he had gone through and just what kind of person he was," McManus said of Miller. "And then when I was having some rough spots that season, he was always giving that support. And coming from a guy like that, what he means in the locker room and on the team, that meant something."

"And pretty soon we were doing all the group stuff we do and B-Mac and me just had the same way of doing things, the same approach, playing cards, whatever, talking about life, it's just one of those people we all have or friends you hope to have, those people who know you, good days and bad days," Miller said. "That's B-Mac."

There are times, McManus admits, that some family members and friends from McManus' pre-NFL life are still inclined to do a double or triple take when Miller, a Super Bowl MVP, rolls into a gathering. That's especially true when McManus' family has a tailgate outside Broncos Stadium at Mile High before and after each home game.

McManus said one of the most enjoyable parts of his career has been the time with his friends and family outside the stadium after each of those home games, win or lose, missed kick or not.

"Out in the parking lot we have that tailgate after the game, no matter how the day went, because I enjoy the sport so much, I enjoy my family coming out to see us play. I'll go out to the tailgate, have something to eat and drink and it really doesn't matter what happened in the game, the weather or anything. Every single time, Von comes by and if I have family members who haven't met him and just can't believe it's him at my tailgate, he'll take photos. It's pretty amazing to watch and funny. You kind of forget how a lot of people see him. I mean, his dad and my dad they go to dinner on the road sometimes, they play pool, to us he's Von."

There are two games left in their fifth season together as teammates, and while the football part of things hasn't gone the way either hoped, they still know they can lean on each other.

"Lot of things he helps me with and some things I've been able to help him with," McManus said. "Sometimes people who are close to him will call me when they want him to do something and I'm the one who talks to him. He'll listen to me."

"That's true, I admit it," Miller said. "That's B-Mac. We just hang every day. I think it will always be like that."