Making the case for Diamondbacks closer candidates as season nears

SCOTTSDALE — Opening Day is two weeks out from Thursday, and the Arizona Diamondbacks continue to evaluate their options to close games this season.
The prime candidates for the role are known, and manager Torey Lovullo would prefer to rely on a closer as opposed to the committee approach. With two weeks until the season begins, this race will go down to the wire.
Conversations between Lovullo, general manager Mike Hazen and assistant GMs Amiel Sawdaye and Mike Fitzgerald are getting more serious. Soon, the group will bring pitching coaches into the discussion.
“We’ll have conversations about what we’re seeing and feeling and how the team fits together here very, very soon, but we haven’t got that far,” Lovullo said Tuesday.
The trio of Kevin Ginkel, A.J. Puk and Justin Martinez has only 43 career saves between them. They each received select opportunities to close games last year.
“It’s kind of like the number one starter thing,” Hazen told Arizona Sports’ Wolf & Luke earlier this spring. “You can’t really say you’re a number one starting pitcher until you go out, like, three years in a row and throw 200 innings, pitch into the playoffs and you become a number one. You have to prove it. The closer is the same thing.”
In the spirit of competition that has been spoken about, let’s make the argument for each case, plus a few wild cards.
Does Kevin Ginkel profile as the Diamondbacks’ closer?
Career in save situations (not only ninth inning): 68.1 innings, 4.35 ERA, 74 strikeouts, 27 walks, 13 saves
Case: Solid for years, trusted in different roles
Ginkel is the elder statesman of Arizona’s bullpen and has performed in just about every role for this club. When it comes to pitching in high-stakes games, he was at his best down the stretch of 2023 and into the postseason, where he delivered 11.2 innings without an earned run and with 15 strikeouts.
The right-hander was the go-to option for closer when Paul Sewald started the 2024 season on the injured list. The results were not perfect, but he received the experience to turn back to. Sewald said last year pitching in the ninth inning is not necessarily harder but it is different.
Ginkel remained a valuable reliever in different spots last year, finishing with a 3.21 ERA and well above average strikeout, walk and whiff rates.
After he allowed a career-high 40% hard-hit rate and his highest exit velocity since 2020, Ginkel has worked on making his lower half more efficient to improve fluidity and his fastball’s verticality. He wants more separation between his four-seamer, slider and two-seamer. This spring, he has thrown four innings with one earned run, five strikeouts and one walk.
“He’s always had that vertical. We’re just trying to incorporate a two-seam to work off his four-seam,” bullpen coach Wellington Cepeda told Arizona Sports. “So we want something not to sink but with more run, so that’s what he’s working on. The slider is his weapon, he can throw that pitch in his sleep. … and he gets both lefties and righties out.”
So far, he’s felt great this spring after he got off to a slow start last year with a sore elbow, and the stuff has been sharp. The Athletic’s Jim Bowden reported Ginkel as Arizona’s spring training standout in a recent column.
“We got some dudes in the back end, so whether it’s myself, A.J., Justin, even (Kendall) Graveman, there’s a lot of guys that can help build that role and be that dude for us,” Ginkel told Arizona Sports. “I look forward to it when I get the opportunity, but at the same time, all I care about is winning.”
GOLD STAR GINKS.⭐️ pic.twitter.com/ylRTcy9YVY
— Arizona Diamondbacks (@Dbacks) July 7, 2024
Can A.J. Puk continue run from end of 2024?
Career in save situations: 76.2 innings, 4.93 ERA, 102 strikeouts, 22 walks, 22 saves
Case: Top performer down the stretch last season
Puk was flat-out unhittable for nearly two months after the Diamondbacks got him at the trade deadline from the Miami Marlins. He allowed one run on Aug. 2 and then zero through Sept. 27.
Just looking at numbers from the start of August, when Arizona moved off Sewald as closer, Puk was in the top five among MLB relievers in strikeouts, strikeout rate and hard-hit rate. Three of the other four in among the top five for K rate were closers.
“He took off with the Marlins … and had an outstanding two or three months here with the Diamondbacks,” said Cepeda, who was Miami’s bullpen coach from 2020-24.
“He’s been confident. He’s been working his tail off right now to get back to where he was … today he was able to get his fastball to the top of the zone. That’s something he’s working on right now. And the slider is continuing to get better. So he’s on the right track right now.”
Just a reminder that AJ Puk had a 1.32 ERA and 43 Ks in 27.1 innings after being acquired at the deadline by the #Dbacks
Puk is still under team control for the next two years pic.twitter.com/xwqcIEmo1P
— Logan🌵 (@phxlogan) December 26, 2024
Puk has also thrown four shutout innings in Cactus League with five strikeouts.
Lovullo has said Puk being a lefty does not disqualify him from the role, despite the club having fewer left-handed options to mix and match than righties. Closers don’t only have to pitch in the ninth inning if the right matchups come up in the eighth, as well.
Like Ginkel, Puk has been a closer during a stretch before, doing so in 2023 with the Marlins to mixed outcomes.
When it comes to most recent regular season results, Puk has the edge.
Justin Martinez is the big-armed youngster who got his feet wet
Career in save situations: 22 innings, 2.45 ERA, 33 strikeouts, 12 walks, 9 saves
Case: Plus, plus stuff and potential
Martinez is throwing 103 mph fastballs this spring.
The stuff is overwhelming, which has been the case, but last year he corralled his arsenal to throw enough strikes to record major league outs.
As a rookie in his age 22 season, Martinez missed a lot of bats to finish 89th percentile in strikeout rate and 96th percentile in whiff rate. He also avoided barrels, as his hard hit rate was 94th percentile, barrel rate 99th percentile and ground ball rate 97th percentile.
“As J-Mart gets older, he won’t be the wild thing anymore,” Hazen said. “He’ll fine tune that command, and then the huge stuff, the swing-and-miss stuff is going to really play. … You need to get strikeouts in some of those moments.”
Puk’s slider-fastball combination was dominant last year, while Ginkel’s slider is his calling card for a reason. But when it comes to a truly devastating pitch the league has yet to figure out, Martinez’s splitter is atop the list.
Last year, opponents slugged .122 against it. Not hit .122, slugged .122.
In terms of strikeout rate, Martinez’s 65.9% using the splitter was the highest of any singular pitch in baseball, minimum 50 plate appearances.
Justin Martinez has the upside to become a Top-10 (or better) reliever for #FantasyBaseball this season.
Splitter: .098 BAA, .122 SLG, 54% Whiff
Slider: .178 BAA, .289 SLG, 45.1% Whiff
Sinker & 4-seam averaged 100+ mphShould be the frontrunner for saves in Arizona. pic.twitter.com/jpyoZIye6G
— Eric Cross (@EricCrossMLB) January 28, 2025
Cepeda has a unique perspective having managed Martinez in the Arizona Complex League in 2019 before he was hired by Miami.
“He’s more mature now … He’s worked his tail off during the offseason to be more consistent,” Cepeda said. “Cutting the walks is something we talk about, especially against lefties, and he’s working on it.
“He’s a really confident kid and he wants the ball. He wants to pitch every day. I like those attitudes. I think he’s going to be really helpful for the team, for the goals that we have to win a World Series.
The walk rate still (11.7%) needs to come down and Martinez is a young pitcher who just received his first taste of high leverage innings last year, but the tools are there for him to take over and hold onto the ninth inning for the foreseeable future. He is not even arbitration eligible until 2027.
Wild cards
— Veteran free agent addition Kendall Graveman has been off to a slow start in spring having signed a couple days into camp and missing time with back tightness. He missed all of 2024 after shoulder surgery, but he previously went on a three-year run with a 2.74 ERA and 24 saves.
— Ryan Thompson has been a stable force in the bullpen since his introduction in 2023, drawing a near league-leading ground ball rate. He very briefly took on closing duties after Sewald last year, but it didn’t stick. He’s worked a 2.84 ERA in 79.1 innings with Arizona.
— Drey Jameson has been an intriguing arm in camp coming off Tommy John surgery. He has lit up the radar gun, hitting triple digits with the fastball that pairs with a slider and a changeup in progress. Formerly a starter, Jameson will not be stretched out at this time as the club works him back in. Whether he makes the Opening Day roster is to be determined, as the club would need confidence he can recover quickly after outings.