The two are involved in a tight competition to win the Detroit Lions starting right tackle spot. It's a competition that could come down to the very last rep. In the end, one will be a starer in the NFL and the other a backup.
Fox and Hilliard sit right next to each other in the locker room and have remained close friends throughout the process. They continue to help each other on the practice field and in the film room.
Hilliard, who's entering his seventh season in the NFL, says it's not always that way in the NFL.
"You have to understand that some people are just ruthless," Hilliard said of past experiences. "I've been in other places where I've watched from afar competitions split people up and guys stop talking to each other and won't help each other out or watch film with the guy.
"I just think this is a special situation for me and Jason. We're good friends and we haven't let the competition deter that. It's been a good competition and we've brought the best out of each other."
Fox sees it the exact same way. In fact, he says because they continue to be friends and help each other out through the process, he, Hilliard and the Detroit Lions are the beneficiary.
"That carries over in practice and on game day," Fox said. "Whether it's one-on-one reps in practice, it's like, 'Hey, good punch there' or 'you drifted a little bit there.' Just coaching each other up and anything to help each other out."
Fox said the two have never once talked about the competition between them. He says they're treating it like any other year when they'd push each other anyways.
"It'll sort out how it sorts out," Fox said. "He's a great player and you have to bring it every day. He's been playing well and has had a great camp. This is the best he's played. I think it's pushing both of us to become better players."
Preseason games don't count, but they do matter when it comes to this particular competition.
In two games, Hilliard has taken 61 reps and Fox 54. That includes both of them taking reps at left tackle in a reserve role.
Ideally, the offensive line the Lions trot onto the field Thursday against the Patriots would be the one they'd like to start Week 1 vs. Minnesota, but that might not be the case at right tackle. That's a competition that could come to the very last practice and last preseason game.
"Again, I don't think we have ever set any time tables," head coach Jim Schwartz said. "We want people that will be consistent over the course of time. We're going to see a lot of different schemes in the preseason from a blitzing 46-type team in the opener, a three-four team, a four-three team. We're going to see a lot of different looks and things like that.
"There's going to be a lot of chances to evaluate those guys. Those guys all play well together. They get a lot of mixing and matching in training and things like that. We'll have plenty of time, once we do get it settled, to get their feet under (them)."
However it works itself out, though, don't expect Hilliard or Fox to be anything other than very good friends when it's all said and done.