The Red Sox have been pursing a major lineup addition for weeks. On Sunday night, they landed one.

Boston has agreed to acquire three-time All-Star Willson Contreras from the Cardinals in a trade, a source confirmed. ESPN’s Jeff Passan first reported the deal.

Boston will send right-hander Hunter Dobbins plus other players to St. Louis in the deal, with those other players still being notified. The Cardinals are taking on some of Contreras’ remaining contract.

Contreras, who played first base for St. Louis in 2025, waived his no-trade clause to come to Boston. He has two years left on the five-year, $87.5 million contract he signed with the Cardinals before the 2023 option, plus a club option for 2028. Contreras is due to earn $18 million in 2026 and $18.5 million in 2026. The 2028 option is worth $17.5 million and has a $5 million buyout, meaning he’s guaranteed $41.5 million on the remainder of his deal.

Contreras, a lifelong catcher who turns 34 in May, shifted to first base for the first time in his career in 2025 and hit .257 with 20 homers, 31 doubles, 80 RBIs and a .791 OPS in 135 games. The former Cub was last an All-Star in 2022 and will provide the Red Sox with an option at first base, designated hitter and potentially, an emergency catching option.

Dobbins, who made his major league debut in 2025, was expected to be ready for Opening Day after missing the second half of the season with a torn ACL. The Texas Tech product looked likely to factor into the Sox’ rotation mix, but the club has felt more comfortable dealing from its pitching depth this winter, especially after adding Gray and Johan Oviedo to the mix.

MassLive first reported the Red Sox’ interest in Contreras earlier this month. At the time, Boston was in talks with multiple teams about bats, including Houston’s Isaac Paredes, Arizona’s Ketel Marte and Contreras’ teammate Brendan Donovan. The Red Sox remain engaged with third baseman Alex Bregman about a return to Boston, as well.

The Contreras trade is the second major deal of the winter between the Red Sox and Cardinals. The teams swung a deal sending Sonny Gray to the Red Sox for pitchers Richard Fitts and Brandon Clarke in late November. Gray, like Contreras, waived his no-trade clause to come to Boston.