Right-hander Walker Buehler and the Boston Red Sox are in agreement on a one-year, $21.05 million contract, sources told ESPN, sending the pitcher who secured the final out of the World Series this year to a team loading up on starting pitching as it pivots toward contention.

The deal, first reported by Yahoo Sports, includes an additional $2.5 million in performance bonuses, sources said.

Buehler, a 30-year-old two-time All-Star who was among the game's best starters from 2018 to 2021, was one of the most fascinating free agents this winter. After undergoing a second Tommy John surgery in 2022, Buehler returned to the Los Angeles Dodgers and allowed a 5.38 ERA in 16 starts.

He remained in the Dodgers' postseason rotation and reinforced his previously established big-game bona fides, throwing four shutout innings in a National League Championship Series win, providing five more shutout innings in a World Series win and then returning on one day's rest to lock down Los Angeles' championship in the ninth inning of a wild Game 5 against the New York Yankees.

Boston hopes Buehler can be every bit as good this October. The Red Sox, who scored the ninth-most runs in baseball last year and have the three best hitting prospects in the game in outfielder Roman Anthony, infielder/outfielder Kristian Campbell and shortstop Marcelo Mayer, went into this winter seeking pitching. And though the shape of it materialized slowly, the Red Sox have managed to add high-upside pitching at a low financial cost.

A blockbuster trade landed them left-hander Garrett Crochet, who projects to be the Red Sox's Opening Day starter for the next two years at low arbitration salaries. And they paid $18.25 million for two years of left-hander Patrick Sandoval, who is expected to return from Tommy John surgery around August.

Buehler carved a reputation as the best kind of bully on the mound -- one who backs up elite stuff with presence and attitude to match. With a four-seam fastball that sat at 96-97 mph and regularly painted the four corners of the strike zone, Buehler could win games with his heater alone. He also happened to throw a cutter, curveball, slider, changeup and sinker, flummoxing hitters on the regular.

His best year came in 2021, a season after he helped lead the Dodgers to their first World Series title since 1988. Buehler went 16-4 with a 2.47 ERA in 207 innings, striking out 212 and walking 52. He finished fourth in tightly contested NL Cy Young voting.

Elbow injuries sidelined Buehler for a chunk of 2022 before he underwent a Tommy John revision with a flexor repair. Players coming back from a second elbow reconstruction -- Buehler had his first in 2015, right after the Dodgers chose him with the 24th overall pick -- work on longer timetables than the typical Tommy John return. Buehler missed all of 2023 and returned in May of this year without his most explosive stuff. Before going on the injured list in June with right hip inflammation, he had struck out just 31 in 37 innings

When he returned in August, Buehler didn't fare any better. Injuries to the Dodgers' rotation reinforced that he was a vital part of their October plans. Over his career, he had put up a 2.94 ERA and struck out 101 in 79 postseason innings. His performance in the 2024 playoffs looked far closer to vintage Buehler than he previously had shown, and his willingness to take a one-year deal rather than pursue a multiyear pact suggests Buehler likewise believes the postseason was merely a preview of what's to come.

If Boston can get the best versions of Crochet and Buehler, as well as a healthy return from Sandoval, its pitching depth will be a distinct strength. The Red Sox also return right-handers Tanner Houck, Brayan Bello, Kutter Crawford and Lucas Giolito, the latter of whom is also coming back from Tommy John surgery.