Diamondbacks' Reliever Hunt Continues Late Into Offseason

A look who among available free agents the D-backs could be interested in.

Arizona Diamondbacks general manager Mike Hazen during spring training workouts at Salt River Fields at Talking Stick near Scottsdale on Feb. 20, 2024. | Rob Schumacher/The Republic / USA TODAY NETWORK

The Arizona Diamondbacks have repeatedly said they are planning to bolster the bullpen this offseason. But as has been well-documented, virtually all of the established free agent "closer" options have been signed already.

The D-backs have indicated they are likely to go with a "bridge" closer, in the hopes they can find a gem similar to Shelby Miller in 2025. The hope is that if they can bridge to the second half of the season, A.J. Puk, and then later Justin Martinez, will return from their respective elbow surgeries to bolster the pen.

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In reality the D-backs likely need to add two solid relievers to the bullpen, one that could potentially fill in as closer, and another to bolster the middle leverage or left-hand roles. They may fill these roles via trade. That is difficult to project who might be available however, so we turn to the free agent lists.

Free Agent Reliever Targets for the Diamondbacks

The table below represents a selected group of pitchers that the Diamondbacks could potentially still be interested in signing. Following that you will find detailed explanations of the table and specific player comments

Free Agent Reliever Targets for 2026 | Jack Sommers

My starting point was sorting the top 15 or so relievers by xERA from 2025 as the D-backs often seem to make moves that dovetail with x stats (both pitching and hitting). xERA is simply xwOBA converted to ERA scale. Baseball Savant explains xwOBA (and thus xERA) as follows:.

"Expected Outcome stats help to remove defense and ballpark from the equation to express the skill shown at the moment of batted ball contact. By looking at the exit velocity and launch angle of each batted ball, a Hit Probability is assigned based on the outcomes of comparable historic balls in play.

"By accumulating the expected outcomes of each batted ball with actual strikeouts, walks and hit by pitches, Expected Batting Average (xBA), Expected Slugging (xSLG), and (most importantly)Expected Weighted On-Base Average (xwOBA) tell the story of a player's season based on quality of and amount of contact, not outcomes."

Then I collected the available projections from 3 different systems, Steamer, The BAT, and ZiPS (a few are not available yet). I averaged those projections, then averaged the projections with the 2025 xERA, and sorted by that number.

Seranthony Dominguez should be no surprise at the top of this table. He is widely viewed as the best power arm still on the market, and will likely make at least $8 million average annual on a two year deal.

Tyler Kinley's raw results numbers over the years have been inflated by pitching his home games in Colorado. But his underlying metrics are solid, and he was terrific for the Braves in 25 innings once he got out of Denver.

Justin Wilson is a 38-year-old lefty that just keeps on putting up solid results year after year. Andrew Chafin is similar, but it seems unlikely the D-backs will go back to that well once again.

Pierce Johnson has already been linked to the D-backs, so it should be no surprise he is on this list. He is coming off a career best season, and has had limited closing experience in the past.

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Danny Coulombe is another veteran lefty that continues to get good results and usually posts ERA lower than his xERA.

Jonathan Losaiga has teased the Yankees for years with his electric stuff, but injuries have gotten in the way of his career. He's only exceeded 40 innings twice, and has thrown just 51 innings over the last three years, including 29 last year.

Kolby Allard is the youngest free agent on this list, but also one of the softest tossers too, with a 90 MPH fastball.

Jalen Beeks performed well for the D-backs early in the season, but injuries to his forearm and back impacted his effectiveness as the season wore on. He was willing to take the ball whenever needed for Torey Lovullo however, and could possibly return.

These eight relievers probably represent the best bets from the table above. Several of them have spent the bulk or even all of their careers in the American League. That could be an advantage, at least for half a season, if moving to the National League.