Butler spent four years playing for Belichick before joining Vrabel and the Titans on a five-year, $61 million contract. That deal came to pass a little over a month after the 28-year-old Butler was effectively benched during Super Bowl LII.
"It's the Patriots system, one of the greatest systems in the NFL," Butler said, via SI.com. "You can tell Mike played for Belichick because you can see some of the similarities. They're about winning the way New England is about winning.
"One thing I saw early: Mike will put you on blast. He don't care who's around. He's going to say what's right. He might be a bit looser than Bill Belichick, but they're both great guys. A man caught a ball on me -- honestly I don't know his name yet -- but Mike let me hear about it. 'Don't get stuck on top of the routes like that! Make a play!' Nobody cares where you come from or what you make. Everyone's equal. And you can tell from the head coach all the way down to the interns, everybody wants to win."
Over the past three seasons, Butler started 47 of 48 regular-season games for New England and seven of eight postseason games. He intercepted eight passes in that three-year span and was selected to the Pro Bowl in 2015.
Butler is best known for making a game-winning interception in the closing seconds of the victory over the Seattle Seahawks in Super Bowl XLIX following the 2014 season.
Vrabel became the 19th head coach in Titans' history in January after replacing Mike Mularkey, who was fired after leading the team to a 9-7 mark in 2017 with a playoff victory.
A former linebacker, Vrabel spent 14 years as an NFL player and the last four as an assistant coach. His playing career included three Super Bowl wins as a member of the Patriots (2001, 2003 and 2004), one Pro Bowl selection (2007) and an All-Pro honor (2007).
Vrabel played with the Pittsburgh Steelers (1997-2000), Patriots (2001-08) and Kansas City Chiefs (2009-10). In 206 NFL games, he had 57 sacks, 496 tackles, 11 interceptions, 20 forced fumbles, nine fumble recoveries and 10 touchdown receptions. In 20 playoff games, he had eight sacks and two touchdown receptions.