How Has Diamondbacks' Bullpen Performed in Spring Training?

The Arizona Diamondbacks have a scheduled off day on Tuesday, as the Cactus League nears a conclusion, with Opening Day on March 27 just nine days away.

There's a lot to be encouraged by this spring, and plenty to be excited about on an exceptionally talented roster ahead of the upcoming season.

One particularly deep unit is the major league bullpen. While this would be a strange sentence to utter not all that long ago, the D-backs' relief group has rapidly turned into one of the major strengths of the club.

While the results of Spring Training don't truly matter, some D-backs relievers have had hot starts, while others have had a more difficult ramp-up process.

Below is a rundown of each major league arm's performance so far in the Cactus League, as well as some of the arms on the outside who might be on the bubble, fighting for a roster spot.

Bullpen Locks

LHP A.J. Puk

In his fifth appearance of the Cactus League, the big left-hander surrendered his first earned run of Spring Training. Over six innings on six appearances, Puk has tossed five scoreless.

He's allowed three walks and three hits, but only one earned run, while striking out an impressive nine batters in that span. Puk looks every bit as dominant and difficult to hit as he did in 2024's regular season, and he profiles as perhaps the best overall reliever in Arizona's bullpen.

Whether those services are called on to close games or simply to offer the best possible arm in any situation remains to be decided, but wherever Puk throws, it's likely to look dominant.

RHP Justin Martinez

Martinez is another name in the closer battle. The 23-year-old flamethrower appears to have his regular season velocity in full swing, even reaching as high as 103 MPH in a Cactus League game.

He has an ERA of 4.50, but that was inflated by one poor outing, in which he gave up three runs against just one out recorded. Of his seven appearances, six of them have been scoreless, with three hits and three walks allowed, while striking out nine of his own.

LHP Joe Mantiply

The reliable left-hander has looked sharp this spring. In 6.2 innings over six appearances, he sports a mere 1.35 ERA with just one earned run.

He's allowed five hits and walked three, while only striking out three, but he's been able to work his way out of base traffic in a fashion similar to what he's been able to do at the major league level.

Mantiply is a useful, versatile arm, and looks to be ready for another successful season.

RHP Kevin Ginkel

Fiery right-hander Kevin Ginkel has been nearly untouchable this spring. Over 5.2 innings, he's allowed only two hits and one walk. Unfortunately, one of those two hits was a solo homer, but that single run is the only thing standing between Ginkel and a perfect spring ERA thus far.

He's struck out seven batters, generated plenty of swing-and-miss, and looks to be in dominant regular season form for the most part.

RHP Ryan Thompson

Thompson has seemed to struggle a bit with his location, as the sinker-slider combo has been knocked around a bit this spring. He surrendered two home runs in an inning against the Texas Rangers, although neither pitch was in an exceptionally poor spot.

But he's only allowed those two runs, with six total hits and two walks and has struck out five. There's little cause for true concern for the sidewinder at this time, as he still sports a solid 2.84 Spring ERA, and should be ready to serve a crucial role again come Opening Day.

RHP Kendall Graveman

Graveman figured to be a prominent aspect of this D-backs' bullpen, but he's been suffering from back tightness, and has yet to pitch in a Cactus League game. After suffering a setback, his status for the Opening Day roster is in question.

If he is healthy, it would be a surprise to not see Graveman in the major league bullpen, but his status remains in the air.

On the Bubble

RHP Drey Jameson

Jameson is in the midst of his long-awaited return from Tommy John Surgery, and he's looked very good in his limited action. Over 5.1 innings, Jameson has allowed just one run, and has eclipsed the 100 MPH mark on his four-seam fastball multiple times.

He's walked three and given up five hits, but has showcased a blend of soft contact and swing-and-miss. If he is able to maintain consistent location, he could force his way into the big league bullpen, and could be dominant there.

RHP Shelby Miller

The reclamation project of Shelby Miller has looked to be successful thus far. After Miller carved himself out a niche as a reliever in the previous pair of seasons, he's looked solid since reuniting with the D-backs this spring.

He's thrown 5.1 innings with two runs given up on four hits. He has not walked a batter, and has struck out seven. Miller is a dark horse to make the roster, but his ability to provide length, coupled with his resurgence as a relief option could help him forge a path back to the Diamondbacks' major league club.

LHP Kyle Nelson

Nelson underwent Thoracic Outlet Surgery this past season, a brutal procedure that often permanently affect's a pitcher's ability. So far, it hasn't looked pretty for the lefty.

Over 5.2 innings, he's been shelled by hard contact and surrendered eight earned runs, walked four, given up a trio of homers and struck out five.

While results aren't everything, his location and movement look to have suffered, and he's been hit hard every time up.

RHP Bryce Jarvis

Another injury survivor, Jarvis has looked generally solid this spring. He sports a 3.38 ERA over 5.1 innings, with two runs allowed on four hits. He's struck out an impressive eight batters, but has also walked five.

Jarvis is also recovering from significant arm injury, but didn't undergo surgery. While the walks are a concern, he's remained capable of pitching his way out of jams, and can provide length.

Jarvis might not be on a deep Opening Day roster, but it feels like a safe bet that the D-backs will call on his services.