According to NFL Network's Ian Rapoport, the deal is for five years and over $61 million, more than $30 million of which is guaranteed.
Butler finished the 2017 season with 60 combined tackles, two interceptions and 12 passes defended. It was a bit of a step down from 2016 when he had four interceptions and was a first-team All-Pro on Pro Football Focus.
This time last year, the Patriots held on to Butler despite signing Stephon Gilmore to a five-year, $65 million deal. Not only did that move signal New England envisioned Gilmore as its No. 1 corner, the details of the contract apparently irked Butler.
The Boston Herald's Jeff Howe reported the Patriots told Butler before the start of the 2016 season they didn't plan on offering any cornerback $10 million-plus per year but then did exactly that with Gilmore.
CBS Sports' Jason La Canfora reported a day before the Oct. 31, 2017, trade deadline New England was willing to move Butler on. Ultimately, a trade failed to materialize.
All of those issues were seemingly bubbling under the surface before things got really bad in the Patriots' Super Bowl LII loss to the Philadelphia Eagles. Butler didn't play a single defensive snap in the 41-33 defeat.
After the game, Butler told ESPN's Mike Reiss and Schefter the Patriots "gave up" on him.
The Patriots' investment in Gilmore didn't quite have the intended impact. New England finished 30th in passing yards allowed (251.2 yards per game) and 21st in pass defense DVOA, according to Football Outsiders, this past season.
Had things not completely broken down between Butler and the Patriots, re-signing him would have made sense. Even if he has taken a step backward, he remains an effective pass defender.
Tennessee, meanwhile, is adding one of the best cornerbacks on this year's free-agent market.
Over the past two years, Butler proved his Super Bowl XLIX heroics were no fluke. He steadily improved over his first three years to the point where he's one of the more consistent coverage guys in the league. He'll make an immediate impact for the Titans' secondary next year.