Sources told ESPN that Carroll has agreed to a four-year, $60 million deal with the Raptors with no options.
The contract can't be signed until July 9, when a leaguewide moratorium on player business is lifted.
After bumping around the league for three seasons during which he was placed on waivers twice, Carroll established a foothold as a defensive specialist and fan favorite with the Utah Jazz. When the Hawks were in search of a 3-and-D wing to fit snugly into coach Mike Budenholzer's system, they dived into the bargain bin and came out with Carroll at two years and $5 million.
With the Hawks, Carroll solidified his reputation as a rugged, handsy perimeter defender and added several offensive components to his game.
Carroll, who will turn 29 in July, averaged 12.6 points, 5.3 rebounds, 1.7 assists and 1.3 steals last season in 31.3 minutes per game with a true shooting percentage of 60.3, far and away a career best.
Marc Stein, Jeff Goodman and Kevin Arnovitz of ESPN.com contributed to this report.