The Dallas Cowboys and Washington Redskins play each other twice a year. They're familiar NFC East foes that have squared off 113 times in history, combining to make up one of the league's best rivalries.
And when they meet on Thanksgiving Day, there will be plenty on the line. The Cowboys, coming in at 9-1, have their eyes set on a first-round bye in the playoffs. The Redskins, on the other hand, are looking to gain some ground on the best team in football, trailing them by three games in the win column.
However, when the two take the field, there will be an added element of familiarity. Cowboys defensive coordinator Rod Marinelli is actually related to a coach on the Redskins side: Joe Barry, Washington's defensive coordinator.
More from FoxSports
Marinelli is Barry's father-in-law, making this game even more meaningful than it already is.
Considering each guy runs the defense for an iconic NFL franchise, there's plenty of competition between them. Marinelli is as competitive and fiery as they come despite being 67 years old. He's always hounding his defenders to rally to the ball, constantly trying to get the most out of every player he coaches. It's one of his best traits, and it's the reason Dallas' defense has been so solid this season with a relatively unknown cast of players.
While there's obviously a rivalry element to their relationship, one that probably carries bragging rights, they still talk regularly. After all, being family (albeit not by blood) makes it hard not to speak to each other. However, they'll probably leave the talking to after the game is over. Before one of last year's games between the Cowboys and Redskins, the two agreed not to talk until after the final whistle.
"It's all elevator music at the end of the day, so I prefer not to say anything," Marinelli said at the time.
The two have a relationship beyond just the fact that Barry married Marinelli's daughter. They've actually been colleagues since 2001, when Marinelli was in his sixth year as the defensive line coach for the Buccaneers. Barry joined the Bucs that year as the team's linebackers coach, holding the title until 2006.
Marinelli left Tampa Bay one year before Barry did, opting to become the head coach of the Detroit Lions. Their time apart didn't last long, though. In 2007, Marinelli recruited Barry to his staff as the defensive coordinator. Unfortunately, putting their defensive minds together didn't work. They went 7-9 in 2007 before making history as the NFL's first-ever 0-16 team in 2008.
In the midst of that season, their relationship was brought into the spotlight thanks to a pointed question by then-Detroit News columnist Rob Parker. After a loss to the Saints, Parker asked Marinelli whether he wished his daughter married "a better defensive coordinator." Marinelli ignored the question before blasting Parker the day after.
"Any time you attack my daughter, I've got a problem with that ..." Marinelli said at the time. "It was premeditated. I think there's something wrong with that."
The two coaches went their separate ways since then, with Marinelli heading to Chicago for a few years before joining the Cowboys in 2013 as the defensive line coach. Barry bounced around from the Buccaneers to USC, spending a year with each. In 2011, he joined the Chargers as a linebackers coach, and four years later he returned to defensive prominence as the Redskins' coordinator on that side of the ball.
Both will be doing their best to net their team a win on Thursday, but they'll do so with great respect for each other.
"He's one of those guys that impacts every single person that he's around," Barry said in 2015. "I don't know if there was ever a day when I didn't get something from him. As a young coach, I think that was huge, because you wake up every day and you're excited to go to work, because you know you're going to get better. You're going to get a little tidbit. And that's what Rod is. Special man, special coach."
Marinelli had equally kind words for his son-in-law, unsurprisingly.
"I think he's smart," Marinelli said. "I think he relates to people really well, communicates very well and is a teacher. Once you have those bases, I think you have a chance to be really good. And he has a great passion for the game."
So when you see Sean Lee make a tackle on Rob Kelley in the backfield, or when Ryan Kerrigan sacks Dak Prescott, just remember that those guys are being coached by members of the same family. It's something they'll certainly be mindful of, to say the least.