Cubs left-hander Matthew Boyd began the road to recovery following left knee surgery necessary to repair a meniscus tear suffered Wednesday playing with his kids.

Boyd was placed on the 15-day injured list on Wednesday and the Cubs are refraining from an official timetable for his return, but he's likely to be ready to throw off of a mound in early June barring setbacks.

Manager Craig Counsell called Boyd's injury innocent but "kind of unexplainable."

Corbin Martin was designated for assignment on Thursday after his blown save against the Cincinnati Reds in Wednesday's game. The Cubs recalled 6-foot-7 right-handed reliever Gavin Hollowell from Triple-A Iowa. Hollowell, 27, pitched in seven games with the Cubs last season and allowed five runs in 9 1/3 innings with seven walks and 10 strikeouts.

Boyd, 35, was on the IL from April 2-21 because of a left biceps strain. He is 2-1 with a 6.00 ERA, six walks and 31 strikeouts in 24 innings over five starts this season.

An All-Star for Chicago in 2025, Boyd is 62-78 with a 4.61 ERA in 218 career appearances (204 starts) for the Toronto Blue Jays (2015), Detroit Tigers (2015-21, 2023), Seattle Mariners (2022), Cleveland Guardians (2024) and Cubs.

Subtracting Boyd from the rotation, at least for a month, gives the Cubs three starting pitchers on the injured list. Boyd joins Justin Steele (left elbow) and Cade Horton (right elbow).

Martin, 30, allowed runs in three consecutive outings, surrendering four hits, four walks and two home runs in those games while facing 11 total batters. He has a 10.80 ERA without a decision in seven relief appearances this season.