The Boston Red Sox made two additions to their bullpen Saturday in the middle of a series against the rival New York Yankees.

Left-hander Bailey Horn was recalled and left-hander Zach Penrod had his contract purchased. Both were promoted from Triple-A Worcester. Left-hander Cam Booser and right-hander Zack Kelly were optioned to Triple-A.

In addition, catcher Tyler Heineman was designated for assignment to open a spot on the 40-man roster for Penrod.

Booser and Kelly each pitched in Friday’s 5-4 loss to the Yankees and recorded one out between them, while getting charged with all five Yankees runs. New York’s Aaron Judge hit a seventh-inning grand slam off Booser.

Booser, 32, is 2-3 with a 3.38 ERA in 43 relief appearances since making his major league debut April 19. Kelly. 29, is 6-3 with a 3.97 ERA in 49 appearances (three starts) and is 7-3 with a 3.95 ERA in 70 appearances (three starts) over three seasons for Boston.

Horn, 26, made his major league debut June 29 and went 1-1 with a 6.35 ERA in 15 appearances. Penrod, 27, is set to make his major league debut after he went 8-2 with a 4.16 ERA in 22 appearances (12 starts) at two minor league levels this season.

Heineman, 33, played in just two games with the Red Sox this season. In 106 career games over five seasons with five different clubs, he is a career .216 hitter with one home run and 15 RBIs.