Donn Mitchell Roach (born December 14, 1989) is an American former professional baseball pitcher.

On May 4, 2012, the Angels traded Roach and Alexi Amarista to the San Diego Padres for Ernesto Frieri.

He allowed eight hits and four runs in 3+1⁄3 innings in his Cubs debut on June 27 as a starter, in a loss to the St. Louis Cardinals.

[12] On December 5, 2015, Roach signed a minor league contract with the Seattle Mariners organization.

[15] In 5 starts for the Triple–A Toledo Mud Hens, he compiled a 3–1 record and 3.03 ERA with 21 strikeouts across 29+2⁄3 innings pitched.

[19] On February 25, 2018, Roach signed a minor league contract to return to affiliated baseball with the Chicago White Sox organization.

[21] On December 30, 2018, Roach signed a minor league contract to return to the Chicago White Sox.

[23] On January 11, 2020, Roach signed with the Uni-President Lions of the Chinese Professional Baseball League.