MLB · 8 months ago

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

SportsGrid Contributor Just Baseball

Host · Writer

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.
5. Shelby Miller – Arizona Diamondbacks
What a turnaround story: released by the Detroit Tigers last season, Shelby Miller is now slamming the door for the Arizona Diamondbacks. By ditching his slider and leaning into a splitter/four-seam combo, he’s found a filthy 30% whiff rate and 36.1% chase rate.

Add his 1.98 ERA, tiny $1 million deal, and proven closing experience, and you’ve got a rental who’ll draw a bidding war from any bullpen-needy contender.

For all your MLB deep dives, check out our friends at Just Baseball.
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.

Stay ahead of the game and elevate your sports betting experience with SportsGrid.
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.

Swing for the Fences with SportsGrid’s free daily MLB Game Picks and MLB Prop Picks.
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.
5. Shelby Miller – Arizona Diamondbacks
What a turnaround story: released by the Detroit Tigers last season, Shelby Miller is now slamming the door for the Arizona Diamondbacks. By ditching his slider and leaning into a splitter/four-seam combo, he’s found a filthy 30% whiff rate and 36.1% chase rate.

Add his 1.98 ERA, tiny $1 million deal, and proven closing experience, and you’ve got a rental who’ll draw a bidding war from any bullpen-needy contender.

For all your MLB deep dives, check out our friends at Just Baseball.

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

BETTING NEWS

FUTURES

EDITOR'S PICKS

For the Best of SportsGrid, Grab the App

BETTING NEWS

FUTURES