The health of Dedniel Nunez hangs over the Mets' pen

A common description of relievers is that they’re fickle. There are at least a couple of things that go into that reality. First, they’re typically not good enough to be starting pitchers, they’re missing something, whether that be endurance, command or enough pitches. And the other thing is that they only pitch a fraction of innings that a starter does. It’s simply easier to put up good numbers in a 60-inning sample (or fewer) than it is to do it over 150 innings. So, a reliever can put up good numbers in one year, only to fall off that pace the following season, a sort of delayed regression, if you will.

Which brings us to Dedniel Núñez. Last year in 35 relief innings in his debut season in the majors, he was outstanding. Nunez posted a 2.35 ERA and a 2.22 FIP, a 0.914 WHIP and he limited opposing batters to a .536 OPS. Injuries and time in the minors kept him from having even a full season for a reliever. So, now the question is: Can Nunez be counted on to be a key member of the 2025 pen for the Mets?

It was not a typical progression to the majors for Nunez. While most top Latin players are signed after they turn 16, the Dominican native was signed at age 20. Nunez put up solid numbers in his first three years in the minors, showing good K and BB numbers for an unheralded prospect. It was enough for the Giants to use a Rule 5 pick on him in 2020.

But Tommy John surgery kept him from every throwing a pitch in the San Francisco organization. He was returned to the Mets after the 2021 season. He had been a starter in his first go-round with the Mets but found himself in the pen as he resumed his career. Nunez fanned 43 batters in 28.1 IP for Double-A Binghamton as a 26 year old in 2022.

Nunez bounced back-and-forth between Double and Triple-A in 2023, doing great at Binghamton but not so hot in Syracuse. After having solid or better command while climbing the ladder, his walk rate ballooned at Triple-A, where he allowed 29 BB in 40 IP for a 6.5 BB/9. That led to a 1.975 WHIP and a 6.75 ERA in his initial exposure to the top level of the minors.

Last season, Nunez rode the shuttle from Syracuse to New York. He made significant improvement with his walk rate, posting a 3.86 BB/9 in Syracuse and a 2.06 mark in the majors. Still, Nunez had three stints in Syracuse before establishing himself with the Mets. And from md-May to mid-July, Nunez worked his way into being perhaps the best arm in the pen.

Unfortunately, Nunez came down with a flexor strain. This injury is a strain or tear of the origin of the flexor-pronator muscles off the medial epicondyle, or the bony prominence many know as “the funny bone.” This type of injury can be a precursor to an ulnar collateral ligament tear, which is what TJ surgery fixes.

There’s not much you can do with the flexor strain – rest, ice and hope for the best. After missing nearly a month, Nunez made one rehab appearance in Syracuse and then one game in the majors before being shut down for the season.

Back in late November there was a tweet from MLB.com’s Anthony DiComo that Nunez was progressing well and that he might make an appearance for Tigres del Licey in the Dominican Winter League. But Nunez has not pitched for Tigres at all and the team has played 49 games. It may be significant or it may not mean anything at all. Nunez has never pitched Winter Ball in his professional career. DiComo also noted that Nunez received a PRP injection but it’s not clear if that was administered during or after the 2024 season.

When healthy last year, Nunez was primarily a fastball/slider pitcher, with the former averaging 96.3 mph and the latter 87.5 mph. Both were plus pitches. Nunez also tossed a handful of sinkers, curves and changes – pitches left over from his days as a starter.

Unlike a lot of other pitchers vying to make the Opening Day roster, FanGraphs has Nunez with options remaining. If healthy, he might be the second-best reliever on the club. And if there’s only so many bullets in his arm before another TJ surgery, is it best to have him use those in Syracuse?

At the end of the day, we have a pitcher who was outstanding in 35 IP. Can the club in good conscience depend on him for a full season with those types of results? Can they take an inferior pitcher north because of concerns about his health, which may or may not be valid? And how does the front office plan for that, given that it has already added pitchers that they like but are out of options? Do they want to sign a top bullpen arm and then risk losing a Paul Blackburn or a Griffin Canning because Nunez is healthy and productive in Spring Training?

The answer is easy for fans, who want to import a high-leverage reliever – or two – and have no qualms about losing anyone like Blackburn or Canning. But that’s not the preferred path for David Stearns. It will be curious to see how Stearns acts with any future pen signings. Are they pitchers with an NRI or are they more-established names, like Ryne Stanek or better? If it’s the latter, it may indicate a concern with the health of Nunez.