The Yankees made a rare trade with the rival Red Sox, sending struggling reliever Adam Ottavino to Boston on Monday along with minor league right-hander Frank German for a player to be named or cash.

As part of the trade, the Yankees agreed to send Boston $850,000 on July 1 to cover part of the $8 million owed to Ottavino, a 35-year-old right-hander entering the final season of a $27 million, three-year contract. New York remains responsible for Ottavino’s $3 million signing bonus, due next Jan. 15.

A Brooklyn native, Ottavino signed with the Yankees before the 2019 season and took No. 0, the Yankees' last available single digit. He had a successful first season that included a 6-5 record and 1.90 ERA as he became a key setup man for closer Aroldis Chapman along with Zack Britton, Chad Green and Tommy Kahnle.

But he slumped to a 5.89 ERA during the pandemic-shortened 2020 season, the highest of his nine full big league seasons, and manager Aaron Boone did not use him with a lead in the late innings of close games in the final week of the season or during the playoffs.

This was just the second trade since 1987 between the rivals. When New York obtained infielder Stephen Drew from Boston on 2014 for infielder/outfielder Kelly Johnson, it was the first Yankees-Red Sox trade since Boston dealt first baseman/catcher Mike Stanley to New York for pitcher Tony Armas Jr. and a player to be named, who became pitcher Jim Mecir.

This trade gives the Yankees flexibility as they try to stay under the $210 million luxury tax payroll threshold. Ottavino figures to count as $924,956 toward the luxury tax payroll for the signing bonus-discounted portion rather than the $8,924,956 entire figure, and his departure cuts the Yankees’ projected tax payroll to $206 million, including $26 million for pending contracts with second baseman DJ LeMahieu and right-hander Corey Kluber plus the rest of their 40-man roster and estimated moves to account for injured players.

New York’s bullpen already was missing Kahnle, who had Tommy John surgery in August, then became a free agent after the season and signed with the Los Angeles Dodgers.

German, 22, was 4-4 with a 3.79 ERA in 2019 in 15 starts and one relief appearance for Class A Tampa of the Florida State League. Minor league seasons were canceled in 2020 because of the coronavirus pandemic.

Boston is retooling after finishing last in the AL East at 24-36. The Red Sox have pending agreements to add free agent second baseman Enrique Hernández and right-hander Garrett Richards and to retain left-hander Martín Pérez.