Entering Diamondbacks offseason, it was clear to nearly every observer around the league that pitching depth represented the most urgent priority for the Arizona Diamondbacks. After a season defined by both promise and fragility on the mound, the front office approached the winter knowing that success in 2025 would hinge not just on star power, but on quantity, durability, and flexibility. While re-signing veteran starter Merrill Kelly provided stability at the top of the rotation, Arizona’s work was far from finished. Instead of relying solely on splashy acquisitions, the Diamondbacks chose a layered approach, quietly accumulating arms that could potentially fill meaningful roles as the season unfolds.
Nowhere was this philosophy more evident than in the way Arizona addressed its bullpen. Last year served as a harsh reminder of just how unpredictable relief pitching can be. Early in the season, injuries struck key relievers Justin Martinez and A.J. Puk, leaving the bullpen thin and forcing the organization to scramble for solutions. That experience reinforced a lesson that front offices across baseball have increasingly embraced: bullpen depth is not a luxury, but a necessity. Relievers are volatile by nature, performance can fluctuate wildly from year to year, and injuries are often unavoidable. The best way to survive that chaos is to stockpile options.
As a result, the Diamondbacks have leaned heavily into non-roster invitations this offseason, bringing in a wide array of pitchers who will compete for bullpen jobs during spring training. These types of moves rarely generate headlines, but they can prove invaluable over the course of a long season. A pitcher who arrives as an afterthought in February can easily become a crucial contributor by June, particularly on a team that expects to be in the thick of the playoff race.
The latest addition to that group came quietly on Friday, when the Diamondbacks signed right-handed pitcher Junior Fernández to a minor league deal that includes an invitation to big league camp. The move was first noted in the official transactions log, a reminder that some of the most interesting roster developments happen outside the spotlight. Fernández is not a household name, but he brings with him both major league experience and a compelling backstory that makes him an intriguing depth option.
Fernández, who will turn 29 years old in March, has already experienced the highs and lows of professional baseball. He made his major league debut with the St. Louis Cardinals in 2019, breaking into the league as a hard-throwing right-hander with an electric arm. Over parts of four seasons with St. Louis, he showed flashes of potential, particularly in terms of raw stuff. His fastball velocity stood out, and at times he looked capable of developing into a reliable bullpen arm.
However, consistency proved elusive. Across 50 career major league appearances, Fernández has logged 54 innings, posting a 5.17 ERA. During that span, he struck out 47 batters while issuing 35 walks, numbers that reflect both his ability to miss bats and his ongoing struggles with command. At his best, he was difficult for hitters to square up. At his worst, control issues and inefficiency limited his effectiveness and put him in tough situations.
In September 2022, Fernández’s time with the Cardinals came to an end when he was claimed off waivers by the Pittsburgh Pirates. That move marked his most recent appearance in the major leagues. Since then, his career path has been anything but straightforward. Over the past three seasons, Fernández has bounced between organizations, spending time in the systems of the New York Yankees, Toronto Blue Jays, Washington Nationals, Kansas City Royals, and New York Mets. For many players, such a journey can signal the beginning of the end, especially when major league opportunities dry up.
What makes Fernández’s situation noteworthy, however, is what hasn’t happened during that time. Despite being absent from the big leagues since 2022, he has not suffered a major injury setback. In fact, he has not been placed on the injured list during that entire stretch. That detail matters, particularly for a pitcher nearing 30, as extended absences from the majors are often tied to health concerns. Instead, Fernández has remained active, healthy, and committed to refining his craft.
Adding to that commitment, Fernández has continued to pitch regularly in the Dominican Winter League during each of the past three offseasons. Winter ball can be demanding, both physically and mentally, but it also offers pitchers a valuable opportunity to face high-level competition and stay sharp. For Fernández, those appearances have served as a lifeline, allowing him to showcase his abilities and remind evaluators that he still has something to offer.
This past winter may have been especially important. Pitching for Águilas Cibaeñas, one of the Dominican League’s most storied franchises, Fernández delivered a particularly strong performance. While winter league statistics don’t always translate directly to major league success, strong showings can reignite interest and open doors that had previously seemed closed. For Fernández, that success appears to have paid off in the form of an opportunity with Arizona.
The Diamondbacks represent an appealing destination for a pitcher in his position. Arizona is a team with legitimate postseason aspirations, but its bullpen remains relatively fluid. Unlike clubs with entrenched relief hierarchies, the Diamondbacks have several roles that will be decided in spring training. That creates a real path to the roster for non-roster invitees who perform well and demonstrate reliability.
From the organization’s perspective, Fernández fits neatly into a broader strategy. He brings experience, durability, and upside, all at minimal risk. If he struggles, the team can simply move on. If he finds consistency and sharpens his command, he could emerge as a useful middle-inning option or depth piece who helps absorb innings over the course of the season.
Fernández is far from the only pitcher vying for such an opportunity in camp. Arizona has assembled a deep group of non-roster bullpen candidates, each with their own strengths and questions. Isaiah Campbell, Shawn Dubin, Derek Law, Jonathan Loáisiga, and Gerardo Carrillo will all enter spring training competing for a spot, creating a crowded and competitive environment. That competition is by design. The more options the Diamondbacks can evaluate in March, the better positioned they’ll be when injuries, slumps, or fatigue inevitably arise.
For Arizona, this approach reflects a realistic understanding of modern baseball. Bullpens are no longer built solely on a handful of trusted arms. Instead, they function as revolving doors, with pitchers moving in and out as circumstances change. Depth is not just insurance; it’s a competitive advantage. Teams that can seamlessly replace a struggling or injured reliever without sacrificing performance are the teams that survive the grind of a 162-game season.
For Fernández, the opportunity represents a chance at redemption and renewal. After years spent on the margins of the sport, he now has a clear shot to reestablish himself at the highest level. At 29, he is no longer a prospect, but he is also not past the point of reinvention. Many relievers find their stride later in their careers, often after refining their pitch mix, improving their command, or embracing a more defined role.
Spring training will ultimately determine whether Fernández’s journey leads back to the majors. He will need to demonstrate not only that his arm strength remains intact, but that he can consistently throw strikes and handle high-leverage situations. If he does, the Diamondbacks may find themselves with another useful piece in what they hope will be a deep and resilient bullpen.
In the end, moves like this rarely grab attention in December or January, but they often loom large by midsummer. Baseball seasons are long, unpredictable, and unforgiving, especially for pitching staffs. By investing in depth and giving opportunities to experienced arms like Junior Fernández, the Arizona Diamondbacks are positioning themselves to weather that uncertainty—and perhaps uncover a contributor who helps push them closer to October.
