Cubs Acquire Reliever Ryan Zeferjahn From Angels

ESPN’s Jeff Passan first reported the agreement, which brings the 28-year-old right-hander to the North Siders in exchange for catcher Moisés Ballesteros and pitcher Mason McGwire.

Chicago entered the day with a 63-49 record, sitting 6.5 games behind the Milwaukee Brewers in the division race. Despite Milwaukee’s substantial lead, the front office has aggressively strengthened its pitching staff for the stretch run. Zeferjahn joins a bullpen reinforcement wave that also includes the reported acquisition of left-handed starter Braxton Garrett from the Miami Marlins.

Zeferjahn’s Strikeout Metrics and Pitch Arsenal

Zeferjahn arrives in Chicago with overpowering stuff, backed by a 3.66 ERA and a 33.5% strikeout rate that ranks in the 97th percentile across the majors, according to Statcast. Across 51 2/3 innings for the Angels this season, he limited opponents to just 30 hits in 45 appearances.

The right-hander relies primarily on a four-seam fastball averaging 97 miles per hour and an 85 mph sweeper featuring 14.8 inches of break. Statcast metrics highlight his ability to miss bats, placing him in the 100th percentile for expected batting average at .161, and the 96th percentile with a 34.6% whiff percentage, according to MLB.com data detailed by Mark Feinsand. While control remains a challenge — he has issued 32 walks this season — his strikeout potency gives the Cubs a reliable arm to navigate high-leverage jams.

Advanced metrics suggest Zeferjahn’s performance has actually been unlucky regarding run prevention. Pitching estimators such as xERA at 2.93 and SIERA at 3.37 place him roughly half a run better than his traditional 3.66 ERA. His dominance has sharpened significantly in recent months, highlighted by a 1.38 ERA and a 41.9% strikeout rate across 26 innings dating back to June 1.

Angels Restock Farm System in Rare Deadline Sell-Off

For Los Angeles, trading Zeferjahn represents the latest move in an uncommon deadline sell-off under interim general manager John Mozeliak. Historically reluctant to deal major league talent during non-competitive seasons under owner Arte Moreno, the franchise has reversed course rapidly.

The Angels sent Logan O’Hoppe and Chase Silseth to the Rangers, followed by trades sending Brent Suter to the Braves, Jo Adell to the Guardians, and Jose Soriano to the Blue Jays. Zeferjahn becomes the sixth player removed from the big league roster in less than a week as the organization works to replenish its farm system.

Ballesteros and McGwire Head to Los Angeles

Heading back to the Angels are two young prospects. Moisés Ballesteros, known affectionately as “Mo Baller,” opened the year as a projected designated hitter and third catcher for Chicago. After a strong April debut, the league adjusted to the 22-year-old, leading to struggles at Triple-A Iowa and ongoing questions regarding his defensive fit on the diamond.

Accompanying Ballesteros is right-handed pitching prospect Mason McGwire, the son of former major league slugger Mark McGwire. An eighth-round draft pick by Chicago in 2022, the younger McGwire missed the entire 2025 season due to injury before returning this year with improved control. Ranked as the Cubs’ 18th-best prospect by MLB Pipeline and 20th by Baseball America, McGwire heads home to Orange County carrying a mid-90s fastball and a sharp curveball.

Role in Chicago’s Bullpen and Long-Term Team Control

Zeferjahn figures to slot into middle-to-late relief innings for a Cubs bullpen currently managed by a committee featuring Jacob Webb, Trent Thornton, and Caleb Thielbar. While Webb anchors late frames with a 2.59 ERA and Thornton and Thielbar handle complementary matchups, Zeferjahn’s swing-and-miss profile provides a vital bridge.

Beyond the immediate stretch run, the acquisition offers roster stability. Zeferjahn is not arbitration-eligible until after the 2027 season and remains under team control through 2030, positioning him to anchor Chicago’s relief corps for multiple seasons.