Reliever Zach Britton agreed to a three-year, $39 million deal to return to the New York Yankees on Saturday, league sources told ESPN, fortifying one of the game's best bullpens after it lost reliever David Robertson in free agency earlier in the week.

Britton's deal includes both a club option and a potential player opt-out, according to sources. The Yankees can exercise a fourth-year option after the 2020 season worth $14 million, making the total value of the deal up to $53 million, sources said.

If the team chooses not to trigger the option, Britton can opt out of his deal, at which point he'll have made $26 million, according to sources.

Britton, 31, a left-hander who turned into one of the most dominant closers in baseball with the Baltimore Orioles, went to the Yankees in a deal for three prospects at the non-waiver trade deadline this past July. He went 1-0 with a 2.88 ERA in 25 innings for the Yankees and finished the season with seven saves and 34 strikeouts over 40⅔ innings in 41 appearances.

In New York, Britton will provide a devastating late-inning complement to closer Aroldis Chapman, right-handed setup man Dellin Betances and fireman Chad Green. The Yankees continue to pursue right-handed free agent Adam Ottavino as well, sources told ESPN.

Britton began the 2018 season on the disabled list after tearing his right Achilles tendon the previous December. He made his debut on June 12 and appeared in 16 games, going 1-0 with a 3.45 ERA and four saves before being traded by the rebuilding Orioles. He did not allow a run in his last eight Baltimore appearances, surrendering just three hits over eight innings.

Zach Britton served as the Yankees' setup man after arriving in a trade at the July 31 non-waiver trade deadline. Paul Bereswill/Getty Images

In 2016, Britton was exceptional. He was 2-1 with a 0.54 ERA and 47 saves in as many chances. He converted an AL-record 60 consecutive save opportunities from Oct. 1, 2015, to Aug. 21, 2017. Over his eight-year career, all but two months with the Orioles, Britton is 31-22 with a 3.10 ERA and 142 saves.

Britton is best known for a devastating sinker, which runs into the high-90s and delivers among the best ground ball rates in baseball. From 2014 to '16, opponents hit .192 with a .254 slugging percentage on at-bats ending on Britton's sinker, according to ESPN Stats & Info. The numbers from 2017-18: .251 batting average against and .331 slugging percentage.

Britton was drafted by the Orioles in 2006 and worked his way up the team's minor league system before landing in the big leagues in 2011.