Game 1 of the best-of-5 series is Friday, while Game 2 is Saturday.
The left-handed Happ has been one of the Yankees' strongest pitchers of late, going 7-0 in the 11 starts he made after being traded from Toronto on July 26. Happ won the first five games he appeared in with the Yankees after the trade.
Happ finished the regular season with a 17-6 overall record and a 3.65 ERA.
He went 1-1 with a 1.99 ERA in four starts against the Red Sox this season. Last week, during the Yankees' regular-season series finale at Boston, Happ gave up a grand slam in an otherwise solid six-inning, seven-strikeout performance.
Since 2015, Happ has been an impressive 5-1 against the Red Sox, compiling a 1.98 ERA with 58 strikeouts and just 23 walks in 12 starts while limiting Boston to a .199 batting average.
Once a candidate to start Wednesday's wild-card game over Luis Severino, Happ brings postseason experience into Friday's opener. He will be making his 11th playoff appearance, and first since 2016, when he was with the Blue Jays.
Boone, meanwhile, said lefties Stephen Tarpley and CC Sabathia are on the ALDS roster, rather than shortstop Tyler Wade and catcher Kyle Higashioka.
Additionally, the Yankees canceled Thursday's planned workout after arriving late to Boston on Thursday. The Yankees advanced to the ALDS after beating the A's in the wild-card game on Wednesday night in New York.
Boone: Red Sox, Yankees in playoffs will be awesome
Yankees manager Aaron Boone talks with Scott Van Pelt about facing the Red Sox and what the intensity will be like in the American League Division Series.