This is a reunion for the Patriots and Collins, as the club had selected him in the second round of the 2013 draft. The agreement was first reported by the Boston Globe.
The team is well stocked at its off-the-line linebacker position, where Collins plays, so there is no guarantee his homecoming results in a roster spot.
Dont'a Hightower and Kyle Van Noy are starters for the Patriots, while 2018 fifth-round pick Ja'Whaun Bentley flashed promise early last year before landing on injured reserve in Week 3. Also, four-year veteran Elandon Roberts returns, with 2018 sixth-round pick Christian Sam among those who will be vying for a roster spot.
Hightower referenced Collins' return on social media Wednesday, posting "He's back.......@j_collins91 #SmashBros back!"
Collins, who led the Browns with 104 tackles last season, was released by Cleveland on March 6. He had been due to earn $10 million in salary in 2019 and $12 million in 2020.
While Collins' play was solid, it was never spectacular. In 30 starts in Cleveland, he had 7 sacks and 4 interceptions. But none was a major game-changing play worthy of a contract that made him one of the highest-paid linebackers in the league.
By releasing Collins, the Browns saved $2.5 million in salary-cap space this season, $9.25 million in 2019 and $13.75 million in 2020.
After missing 10 games during the 2017 season after having surgery for a torn medial collateral ligament, Collins returned to start all 16 games in 2018. In addition to leading the team in tackles, he had 4 sacks, an interception, a forced fumble and a fumble recovery.
The Browns traded for Collins the season after he led the Patriots in tackles and went to the Pro Bowl. Cleveland then signed him to a four-year, $50 million contract before he hit free agency in 2017.
ESPN's Mike Reiss contributed to this report.