2025 MLB Trade Deadline: Ranking the Top Rental Relief Pitchers on the Market

1. Ryan Helsley – St. Louis Cardinals

The big question in St. Louis: push for a crowded NL Wild Card or flip premium arms and retool? If the St. Louis Cardinals choose the latter, Ryan Helsley becomes the crown jewel of rental closers.

He’s not lights-out compared to past seasons, but “Hells Bells” still boasts elite stuff that any contender dreams of plugging into the ninth. In a contract year with swing-and-miss heat, Helsley’s name will be hot in deadline talks.

Thanks to Just Baseball for the stats, analysis, and insights for this slideshow article.

4. Steven Matz – St. Louis Cardinals

Nobody had Steven Matz circled as a bullpen rental in spring, but here we are. The lefty has reshaped his value by thriving as a multi-inning reliever and opener, logging 47 innings, a 3.45 ERA, and doing it all in a contract year.

If the St. Louis Cardinals are willing to cover part of his $11 million, Matz’s flexibility could net them a real prospect haul. Multi-inning lefties don’t grow on trees in October.

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3. Phil Maton – St. Louis Cardinals

Phil Maton is the classic low-cost, high-leverage rental teams love to snag. After bouncing to the New York Mets at last year’s deadline (posting a 2.51 ERA in 31 games), he’s back in the shop window with a fresh one-year, $2 million tag.

He’s carrying a 1.91 ERA, a 12.0 K/9 with the St. Louis Cardinals, and is living in the 99th percentile for Average Exit Velocity. More curves, fewer barrels — Maton is built for late innings on a playoff roster.

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2. Aroldis Chapman – Boston Red Sox

The Boston Red Sox haven’t exactly been a model of calm this year — off-field drama and the Rafael Devers deal made waves, but Aroldis Chapman could flip the script for a contender.

At 37, he’s still humming fastballs at 99 mph, striking out 13.3 per nine and walking a career-best 2.5 per nine. His 1.25 ERA and 1.70 FIP back up the stuff, and if Boston eats a chunk of his $10.75 M tab, a big return is possible.

Oh, and the last few times Chapman was dealt? His new team won the World Series. Worth remembering.

1. Ryan Helsley – St. Louis Cardinals

The big question in St. Louis: push for a crowded NL Wild Card or flip premium arms and retool? If the St. Louis Cardinals choose the latter, Ryan Helsley becomes the crown jewel of rental closers.

He’s not lights-out compared to past seasons, but “Hells Bells” still boasts elite stuff that any contender dreams of plugging into the ninth. In a contract year with swing-and-miss heat, Helsley’s name will be hot in deadline talks.

Thanks to Just Baseball for the stats, analysis, and insights for this slideshow article.