FOXBOROUGH, Mass. -- In his 19 years as New England Patriots head coach, Bill Belichick has never experienced what will unfold Sunday when his team visits the Tennessee Titans. For the first time, the opposing head coach will be one of his former players, Mike Vrabel.

Not that Belichick was necessarily forecasting who might be his first player to become an NFL head coach, but if he were, Vrabel would have been close to the top of the list.

“I'm very fortunate to have had a great relationship with Mike through the years -- when he played, and then when he went into coaching, starting at Ohio State, and continued on to the Texans and now in Tennessee,” Belichick said Monday.

“Mike has a lot of great qualities as a person, and that translates into being a good coach. He works hard. He's physically very tough and has a great passion for the game. I think you saw that in his playing.”

Vrabel, who played for the Patriots from 2001-08, was known for physical and mental toughness, coming through in the clutch and his intelligence, among other things. He was part of the core of players who helped the Patriots win Super Bowls in the 2001, 2003 and 2004 seasons.

Best of NFL Nation • Jones vs. Kamara a big SNF matchup

• Urschel goes from NFL to MIT

• Belichick: Waller will be a challenge

• Bolder Kyler Murray still humble

• McCarthy might have Cowboys moment

“He's very astute and picks things up quickly; has a good aptitude for football. I think the game comes fairly easily to him in terms of understanding concepts and situations and things like that,” Belichick said. “He was a great player here, one that hopefully will be recognized into the Patriots Hall of Fame. I certainly think he deserves to be there.”

Vrabel has been a finalist in each of the past two years, edged out by Raymond Clayborn in 2017 and Matt Light in 2018.

The relationship between Belichick and Vrabel did have one rocky patch, however.

"Bill was my coach; he traded me to Kansas City and we didn't talk for a couple of months, maybe a year," Vrabel said. "Then we became friends and I used him as a resource when I started my coaching career. I still talk to him a lot now. This week we're competitors. I guess it's unique from that standpoint."

And there's no doubt that Vrabel's time playing for Belichick affected how he coaches.

"I think spending time there, there are some similarities that I believe in and you grow up as a player believing in," Vrabel said. "We have different personalities. I respect his friendship and his guidance and leadership when I played there. Now we're competitors and we have to do everything we can to beat the Patriots."

Quarterback Tom Brady remains one of Vrabel's close friends.

“Mike would be successful at anything he does in in life because he’s that kind of guy. We’ve been friends for almost 20 years, and we keep in touch regularly,” Brady said in his weekly interview on sports radio WEEI. “He’s smart, hard-working; he’s so charismatic, just a great leader of men. Tennessee is lucky to have him.”

Vrabel’s tenure with the Titans got off to a 3-1 start, but the club lost three in a row before beating the Dallas Cowboys 28-14 on Monday night. Facing a Vrabel-coached team will add another layer to their friendship and competitive banter between them.

“I loved playing with him, I love hanging with him, and I’m sure those guys in Tennessee love playing for him,” Brady said. “It’s going to be a great game.”

ESPN Tennessee Titans reporter Turron Davenport contributed to this story.