Cubs left-hander Matthew Boyd is going to undergo surgery to address an injury to the meniscus in his left knee. His current timetable is unknown. Manager Craig Counsell provided the update to reporters, including Jesse Rogers of ESPN. After Counsell spoke, the Cubs officially placed him on the 15-day injured list. Right-hander Trent Thornton was selected to take Boyd’s spot on the roster. Left-hander Charlie Barnes was designated for assignment to open a 40-man spot for Thornton. Jordan Bastian of MLB.com reported that Thornton would be coming up prior to the official announcement.

The Boyd injury comes out of nowhere. He started for the Cubs on Sunday and tossed six innings of two-run ball against the Diamondbacks. Apparently, Boyd first noticed the injury while getting up and down to play with his kids, per Patrick Mooney of The Athletic. That led to an MRI, which showed an issue with his meniscus. His timeline won’t be known until after the procedure takes place, per Mooney, but it will be longer than a minimum stint on the IL.

For however long Boyd is ultimately out, it will be a blow to the Cubs. They have already lost Cade Horton to Tommy John surgery, so he’s done for the year. Justin Steele is trying to come back from his own elbow surgery but a flexor strain recently pushed his timeline and he’s probably out beyond the All-Star break now.

The Cubs started the year with Horton, Boyd, Edward Cabrera, Jameson Taillon and Shota Imanaga in five spots. Boyd missed time earlier due to a bicep strain. Due to that ailment and Horton’s surgery, Colin Rea moved from the bullpen to the rotation and Javier Assad was called up from the minors. When Boyd returned from the bicep issue, Assad was bumped to the bullpen.

Boyd’s spot in the rotation is due up on Friday. Perhaps Assad will get another rotation gig but he’s not currently stretched out. His last start was April 19th, when he went 5 2/3. He then pitched one inning on April 23rd and 2 1/3 on April 25th, followed by a big gap. He tossed an inning and a third last night, his first game action in ten days.

Doug Nikhazy is on optional assignment and could be another option but he lasted only 2 2/3 innings in each of his two most recent Triple-A starts. Guys like Ty Blach, Connor Noland, Paul Campbell and Will Sanders have been starting in Triple-A but aren’t on the 40-man and no one in that trio has an ERA below 6.00.

For now, Thornton gives them an extra arm in the bullpen. The Cubs signed him to a minor league deal in the offseason. He has made four Triple-A appearances, logging 5 2/3 innings with a 3.18 earned run average, 20% strikeout rate and 12% walk rate.

He is coming off a pretty decent three-year run in the big leagues. From 2023 to 2025, mostly with the Mariners, he tossed 146 innings with a 3.58 ERA, 22.5% strikeout rate, 6.5% walk rate and 40.1% ground ball rate. Unfortunately, he tore his left Achilles last summer, ended his season prematurely. That led Seattle to non-tender him, which allowed the Cubs to scoop him up on a minor league pact.

Ideally, he’ll get back on track and be a useful piece of the Chicago bullpen. If it doesn’t work out, Thornton has at least five years of big league service time, meaning he can’t be optioned to the minors without his consent.

Barnes, 30, signed a minor league deal with the Cubs in the offseason and was added to the roster about two weeks into the season. He made one big league appearance, tossing three innings of relief on April 13th, allowing three earned runs. In Triple-A this year, he has tossed 21 2/3 innings with a 3.74 ERA, 25.8% strikeout rate and 12.4% walk rate.

He’ll now head into DFA limbo, which can last as long as a week. The waiver process takes 48 hours, so the Cubs could take five days to field trade interest, though they could also put him on waivers sooner than that. He spent 2022 to 2025 pitching in South Korea, posting a 3.58 ERA for the Lotte Giants. Since he still has options, perhaps that will entice some clubs in need of pitching depth, but the Cubs are one such club and they’re bumping him off the roster.

Photo courtesy of Matt Marton, Imagn Images