The Yankees bolstered their pitching for the stretch run and playoffs, obtaining starter Frankie Montas and reliever Lou Trivino from the Oakland Athletics on Monday for four prospects.

New York sent Oakland 26-year-old rookie left-hander J.P. Sears along with three minor leaguers: 24-year-old left-hander Ken Waldichuk, 23-year-old right-hander Luis Medina and 22-year-old infielder Cooper Bowman.

Earlier in the day, the Yankees got Scott Effross, a 22-year-old rookie reliever, from the Chicago Cubs for Hayden Wesneski, a 24-year-old minor league right-hander.

Montas, a 29-year-old right-hander, is 4-9 with a 3.19 ERA in 19 starts. He was the second significant starting pitcher dealt ahead of Tuesday’s trade deadline after Cincinnati sent Luis Castillo to Seattle.

Montas has a $5,025,000 salary this year, is eligible for arbitration this winter and can become a free agent after the 2023 season. His fastball averages 96 mph.

Trivino, a 30-year-old right-hander, is 1-6 with a 6.47 ERA — double his 2021 figure — and 10 saves in 13 chances. He has a $3 million salary, is eligible for arbitration ahead of the 2023 and 2024 seasons, then can become a free agent.

Sears is 2-0 with a 2.05 ERA in two starts and five relief appearances.