Checking in on Justin Martinez, A.J. Puk as D-backs’ bullpen works through transition

SAN FRANCISCO — The Arizona Diamondbacks’ bullpen transitioned over the past month after moving Paul Sewald out of the ninth inning, favoring 23-year-old Justin Martinez in the de facto closer role.

No closer has been formally named despite Martinez receiving those opportunities for weeks. Sewald has not performed to a point where his reinstatement is obvious, despite manager Torey Lovullo’s comments that the best version of this bullpen has a clicking Sewald on the back end.

Lovullo said Martinez is on the right track, but what would the D-backs do if the postseason started today?

“It’s hard for me to project. I’m just going to take it day-by-day with the group we have,” Lovullo said. “We got to win games, and however that happens, we’re going to continue to piece together the best way we can. If I have to say somebody’s closing by the end of the season, I will, but up until that point, I’m gonna be as fluid as possible.”

Arizona’s first two games in San Francisco were not clean for the “positive-role” bullpen after the lower-leverage arms got the brunt of the work while trailing in games against the Los Angeles Dodgers over the weekend.

Ryan Thompson, Kevin Ginkel and Martinez each allowed multiple runs at Oracle Park. Martinez gave up runs in back-to-back games, although he finished off both wins.

Ginkel previously had a 12-game scoreless streak, while Thompson has not seen the same results since Sewald’s demotion (8.76 ERA, 3.55 FIP since Aug. 2).

A.J. Puk has been Arizona’s most effective reliever since joining the team at the trade deadline. He is up to 16 innings with one earned run and 26 strikeouts. He struck out all four hitters he faced to open the Giants series.

“I’ve thought about that,” Lovullo said after Tuesday’s 8-7 win. “He could (close) if there’s a wall of lefties, for sure. I could see him finishing a game … I’m gonna go matchup based. I like what J-Mart’s doing right now.”

Justin Martinez learning what it takes to close in Diamondbacks’ bullpen

Martinez since his first save on Aug. 5 has a 3.68 ERA and 2.91 FIP, striking out 22 batters in 14.2 innings. He has also allowed 16 hits, mostly singles. Martinez does not have a blown save in that span but owns three losses as he goes through the ups and downs of taking on a heightened role.

The young flamethrower told Arizona Sports through a Spanish interpreter he needs to be more aggressive to get ahead in counts.

He has exceptional stuff but has to give himself the best chance to attack. That opens up his optionality with the splitter and slider, pitches that draw whiffs roughly half the time (53.7% on splitter, 46.7% on slider).

“J-Mart, of all the guys we have possibly outside of Puk, he’s the one guy who can overwhelm you with stuff. The problem is J-Mart is a young pitcher and he’s throwing ball one to a lot of hitters,” pitching coach Brent Strom told Arizona Sports. “That limits his ability to use his split as well as he can. He’s done well for a young pitcher put in a tough situation and handles it well. He wants to be good. He wants to be a closer.”

Strom said hitters can put wood to a bullet if they get their foot down in time. Martinez can fire 102 on the radar gun, but opponents can poke it into the outfield when they sit on the heater and see one in the zone.

“J-Mart doesn’t have an exceptionally hoppy fastball like (Ryne) Nelson does,” Strom said. “He’s got to do a two-seamer to create movement. He has to use his slider, which has become a really quality pitch. It’s just been a maturation for him over this year.”

Lovullo has likewise highlighted Martinez’s improved mound presence, saying that maturity is as important as anything. He does not want to know how well a pitcher is performing by looking at his body language out there. The last two nights did not go perfectly for Martinez, but he made pitches to end both games on top.

Martinez debuted last season, and walks and homers doomed his first cup of coffee. From that point, however, becoming a major league closer has been a dream. Martinez did not start pitching until he was 16, as he grew up an outfielder in the Dominican Republic. But he is in lockstep with Lovullo understanding he is not there yet.

“He hasn’t really paid attention to how much progress he has made since he first joined the team to now being this close to having that opportunity, because he doesn’t think it belongs to him yet, but he gives credit of having that mindset of one day being the guy,” Rolando Valles interpreted for Martinez. “So it’s just a byproduct of all of his energy and thought process, the fact he’s getting an opportunity.”

Martinez has appreciated the help from a veteran bullpen group, along with Arizona’s catchers and infielders such as Geraldo Perdomo, Ketel Marte and Eugenio Suarez for helping to calm him down at the mound in certain spots.

A.J. Puk is on quite a run

Puk is on a 12.2-scoreless innings streak over his last 15 games, and it gets crazier than that. Dating back to his time with the Marlins, Puk has allowed one earned run over his last 32.2 innings since June 19 with a staggering 51 strikeouts. That’s a 0.28 ERA.

“Just attacking hitters, getting ahead and being able to locate some pitches I’ve been working on,” Puk told Arizona Sports. “It’s all about getting ahead. … Just being able to locate and keep your emotions in check. Just because it’s higher leverage, don’t let the pressure get to you, just go out there and compete.”

The lefty has proven to be a critical addition by the front office with questions circulating around the pitching staff.

Lovullo said on Tuesday he was not worried about the back end of the bullpen, especially Thompson given his value to the club since last season.

Arizona’s bullpen since the start of August has a 4.33 ERA, which ranks 18th, although the peripherals are much better (3.15 FIP, 3.56 expected ERA).

Getting the pitching as a whole straightened out — longer starts are needed to help the bullpen — with how lethal the offense has been can open doors for the Diamondbacks, with perhaps no better evidence than last October’s run.

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