Dorsett, 28, is a former first-round pick by the Colts in the 2015 NFL Draft. The Patriots acquired him from the Colts in exchange for QB Jacoby Brissett.
Dorsett re-signed with New England on a one-year deal after his rookie contract expired in 2019. The Seahawks later signed Dorsett to a one-year contract last year, but missed the entire season with a foot injury.
Dorsett had signed a one-year, $1.1 million deal with the Jaguars in March.
In 2019, Dorsett appeared in 14 games for the Patriots and caught 29 passes for 397 yards and five touchdowns. He also carried the ball three times for 21 yards.