The Patriots will also send Las Vegas a 2023 seventh-round draft pick in return for the Raiders' sixth-round selection, according to a source.
Stidham, who at one point was considered a top candidate to replace Tom Brady in New England in 2020, enters his fourth season in the NFL and will vie for a backup spot behind starter Derek Carr in Las Vegas. He will compete against Nick Mullens for that role.
The trade also reunites Stidham with Raiders first-year coach Josh McDaniels, who was Stidham's offensive coordinator in New England for the past three seasons.
SI.com first reported the trade Thursday morning.
Stidham's time with the Patriots took several notable turns. The former Auburn star was selected in the fourth round of the 2019 draft and quickly ascended to the No. 2 role behind Brady in his rookie season.
When Brady departed for the Tampa Bay Buccaneers in free agency in 2020, Stidham seemed primed to elevate to the starting role before New England signed veteran Cam Newton in the weeks leading up to training camp. Newton quickly earned the No. 1 job, and veteran Brian Hoyer also beat out Stidham for the top backup spot.
In 2021, Stidham's path was blocked again when the Patriots selected quarterback Mac Jones in the first round of the draft. Stidham's standing on the 2022 roster was placed in jeopardy when the Patriots selected Western Kentucky quarterback Bailey Zappe in the fourth round of the draft.
Stidham has appeared in eight games over his three NFL seasons, all as a reserve. He has completed 48 of 124 passes for 270 yards, with two touchdowns and four interceptions.
He has one year remaining on his contract and is scheduled to earn a base salary of $965,000. The Patriots have been tight to the salary cap, and trading Stidham provides some short-term relief.