Michael Kopech allows 1 run in 3-plus innings in his first start since 2018 as the Chicago White Sox win 5-1 to sweep the Boston Red Sox in a doubleheader

BOSTON — The Chicago White Sox needed a starter for the second game of Sunday’s split doubleheader against the Boston Red Sox.

Michael Kopech was ready for the assignment.

The hard-throwing right-hander allowed one run on one hit with four strikeouts and one walk in three-plus innings in his first start in 31 months, and the White Sox swept the doubleheader with a 5-1 victory in Game 2.

Kopech retired the first nine batters he faced. He walked Enrique Hernández to begin the fourth, and Alex Verdugo followed with a single. Kopech exited, having thrown 41 pitches.

It was Kopech’s first start since Sept. 5, 2018, against the Detroit Tigers. The next day, he was diagnosed with a torn right ulnar collateral ligament and underwent Tommy John surgery Sept. 18.

He missed all of 2019 while recovering and opted out in 2020 for personal reasons.

While the long-term plan is for Kopech to start, he made a temporary transition to the bullpen for this season. He has excelled in the role with a 1.17 ERA and 13 strikeouts in 7 2/3 innings over four relief appearances.

The Sox had options after Dallas Keuchel went five-plus innings in Sunday’s first seven-inning game, and Kopech got the ball.

“He’s fired up and we’re fired up to watch him,” Sox manager Tony La Russa said before the game.

Kopech, 24, threw a 95 mph fastball for a called strike on his first pitch to Hernández. And he kept throwing strikes against his former organization.

The Red Sox selected Kopech with the No. 33 pick in the 2014 draft. They traded him to the White Sox in a package that also included third baseman Yoán Moncada for Chris Sale in December 2016.

Sunday marked Kopech’s second start against the Red Sox. He pitched three scoreless innings in an Aug. 31, 2018, start at Guaranteed Rate Field, striking out one, and was removed from the game after a lengthy rain delay.

Sunday, he struck out one in the first, two in the second and one in the third.

Nick Madrigal and Yermín Mercedes led the way offensively. Madrigal had two hits, two RBIs and scored once. Mercedes hit a 431-foot solo home run during a three-run fourth as the White Sox built a 4-0 lead.

Matt Foster, who La Russa said was another option to start in Game 2, followed Kopech. He pitched well, allowing one hit and striking out two in 1 2/3 innings. Garrett Crochet (one-third of an inning), Evan Marshall (one inning) and Liam Hendriks (one inning) closed it out as the White Sox returned to .500 (8-8).