Chicago Cubs left-hander Shota Imanaga was placed on the 15-day injured list with a strained left hamstring on Monday.

The Cubs are now without Imanaga and a second top starter — Justin Steele — as they begin a three-game home series with the San Francisco Giants on Monday.

Because of an off day Thursday, the Cubs could skip Imanaga's turn in the rotation.

In eight starts this season, Imanaga (3-2) has posted a 2.82 ERA with 34 strikeouts and 14 walks in 44⅔ innings. He was the Cubs' lone All-Star last season as a rookie and started on opening day this year in the Tokyo Series against the Dodgers.

Imanaga was injured in the sixth inning of a scoreless pitcher's duel Sunday with the Brewers and Freddy Peralta when he reached for the back of his left leg in pain.

Imanaga also left his previous start on Tuesday against the Pittsburgh Pirates in the sixth inning with leg cramps.

Right-hander Gavin Hollowell joined the Cubs on Monday from Triple-A Iowa and is expected to work out of the bullpen.

Steele was placed on the 15-day injured list with left elbow tendonitis on April 9. He is set to miss the rest of the 2025 season after undergoing surgery last month.