Cubs trade for lefty Tom Cosgrove, part ways with Caleb Kilian

The Cubs completed a trade on Wednesday that closes the book on one of the major trades in recent team history.

The team announced they acquired left-handed pitcher Tom Cosgrove from the San Diego Padres for cash considerations and optioned him to Triple-A Iowa. The team designated right-hander Caleb Kilian for assignment to make room on the 40-man roster.

Kilian had been acquired at the 2021 trade deadline from the San Francisco Giants along with outfielder Alexander Canario for Kris Bryant, the homegrown, National League Rookie of the Year, Most Valuable Player and World Series champion. Canario was designated for assignment during spring training and was subsequently traded to the New York Mets and later DFA’d by the Mets and now is with the Pirates.

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Cosgrove, 28, was designated for assignment on Sunday by San Diego. He was a solid reliever just two seasons ago. The lefty posted a 1.75 ERA and 0.97 WHIP with a save and seven holds in 51.1 innings across 54 outings in 2023.

But he had a difficult 2024 campaign. He missed a month with left elbow inflammation and was funneled between San Diego and Triple-A El Paso. Cosgrove made 18 appearances and had an 11.66 ERA and 1.98 WHIP in 14.2 innings in the majors.

He’s another left-handed relief option for manager Craig Counsell. The Cubs have just one in their major-league bullpen – Caleb Thielbar – and just one more on the 40-man roster, Luke Little. Cosgrove throws from a side-arm angle and relies on a sweeper, sinker and four-seam fastball mix. He threw the sweeper 52.2 percent of the time in 2023, and opponents hit just .153 off that pitch. It was still effective last season – opponents hit .208 off it in 2024.

Kilian, 28, was in Double-A when the Cubs traded for him. He reached the majors in 2022 but struggled in parts of three seasons in the majors. He made eight appearances, five starts in the big leagues and was 0-4 with a 9.22 ERA and 2.01 WHIP.

Kilian battled injuries in 2024 when he looked poised for a breakout. He missed four months last season with a teres major strain in his shoulder during spring training. That was after posting a 1.50 ERA in six Cactus League appearances.

He was granted a fourth option year in 2025 and made one appearance with the I-Cubs this season, allowing six earned runs on three homers in 2.1 innings of work. He was placed on the seven-day injured list on Saturday.