NEW YORK – Less than an hour before first pitch on Friday night, the Red Sox announced that Tanner Houck was being scratched from his scheduled start with “right shoulder fatigue.”

Houck last pitched on September 4, when the Red Sox were in New York playing the Mets. He went five innings, struck out seven, and issued one walk, but allowed four earned runs on five hits.

Over 28 starts in his first All-Star season, Houck owns a 3.24 ERA and 1.167 WHIP, with 150 strikeouts over 169 ⅔ innings. He’s already blown past his previous career-highs in starts, innings, and strikeouts.

In two starts against the Yankees this year, Houck posted a 3.86 ERA over 9 ⅓ innings. The Bronx batters hit .212 against him with a .630 OPS.

Richard Fitts will start instead. The right-hander, 24, was among the pitching prospects acquired from the Yankees in the Alex Verdugo trade last December. The Red Sox called Fitts up last Sunday, and he made his MLB debut against the Chicago White Sox.

In addition to the concerning late scratch of Houck, there are implications for the Boston bullpen. Key arms, including Justin Slaten, Chris Martin, and closer Kenley Jansen, each pitched an inning in Thursday night’s series opener. The Red Sox also used Cam Booser, Zack Kelly, and Josh Winckowski. On Friday afternoon, when Houck was still slated to start, manager Alex Cora said they planned to use Fitts in a relief role.

Instead, the Red Sox will rely on the rookie Fitts, who will have to find a way to shut down some of the most powerful bats in baseball in just his second career start.