Boston Red Sox right-hander Walker Buehler has been scratched from Friday night's start against the visiting Minnesota Twins due to issues with his pitching shoulder.

Buehler left the team while it was in Toronto to travel back to Boston to undergo testing on the shoulder.

"We're working on a few things regarding Walker. We'll see where we're at over the weekend," Red Sox manager Alex Cora said before Thursday's game against the Blue Jays. "He hasn't bounced back the way we wanted, so we have to wait."

Buehler, 30, last pitched on Saturday when he defeated the Cleveland Guardians to improve to 4-1 in six starts. He gave up three runs and seven hits in six innings, striking out three and walking one.

Buehler has a 4.28 ERA with 29 strikeouts against nine walks in 33 2/3 innings.

Soreness in Buehler's pitching arm always leads to concern.

Buehler has undergone two Tommy John surgeries during his career, and the latter one in 2022 caused him to miss the entire 2023 season and make his 2024 debut in May.

Buehler last made it through a full season without issue in 2021 when he made a career-high 33 starts. He went 16-4 with a 2.47 ERA that season.

Right-hander Brayan Bello (2-0, 3.27 ERA) will be the Friday starter for Boston against Minnesota.

The Red Sox also scratched impressive rookie Kristian Campbell (rib discomfort) from Thursday's lineup. The 22-year-old is batting .301 with four homers and 12 RBIs in 29 games.