Let’s look at the rest of the spring pitchers outside the 40-man roster
Listher Sosa (79)
You might be forgiven for having missed the news of Sosa’s arrival on the Diamondbacks. It happened late in spring of 2022, when we traded Josh Van Meter – remember him? – to the Pirates for Sosa. Nobody paid much attention. Three years later, Sosa will be playing with the big boys, coming off a season which saw him play at three different levels, finishing at Double-A. His results were a bit up and down, but seemed to put things together down the stretch. Over his final 32.2 innings, including his promotion up to Amarillo, he had a 1.65 ERA and a 33:8 K:BB ratio, reportedly reaching close to three digits with his fastball. Still only 23, Listher could end up being more productive for us than Van Meter ever was!
Thyago Vieira (49)
Our only Brazil-born player ever, Vieira was plucked off waivers from the Orioles in June, and initially looked good here, posting a 2.87 ERA for the Diamondbacks across 15.2 innings. However, that was kinda lucky, with an FIP approaching two runs higher, at 4.76. That’s likely why the team opted to drop him off the 40-man roster, to make room for A.J. Puk. But Vieira went unclaimed and so stayed with Arizona. On August 9, he went on the restricted list for Reno, but nobody seems to know why. Whatever it was, however, all seems sorted now, and he’ll have a shot to re-establish his credentials, as a potential mid-season call-up for the D-backs bullpen. Improving that K:BB ratio last year from 39:26, would be of help.
Josh Winder (71)
The most experienced player in this batch, Winder has pitched 110.2 innings for the Twins over the last three seasons, to an ERA of 4.39 (ERA+ 93). Once deemed good enough to play in the 2021 Futures Game, his career path seems to have been impacted by shoulder injuries, likely factoring into his move from the rotation to the bullpen. But he still had a late start to last season in the minor, with a stress fracture of his right shoulder blade, detected in an October 2023 MRI. Even when he did play, he had a 6.15 ERA in Triple-A, though how much of that was a physical thing, I can’t say. It’s the kind of low-cost flier for which spring is made, but staying healthy would be the top priority for Josh.
Kyle Backhus (86)
Moving on the two left-handed pitchers, we start with Backhus, who went undrafted out of college, but signed as a Diamondback in 2021. He was also a non-roster invitee last year, and there were expectations he might make his major-league debut. But Kyle ended up missing almost the first two months through injury. He performed well in Reno, but might have ended up running out of steam. After posting a 2.89 ERA through his first thirty appearances for Reno, his last half-dozen inflated his season figure by more than a run, to 3.94. That’s still decent for the PCL, and the shortage of left-handers ahead of him on the 40-man roster may play to Backhus’s advantage.
José Castillo (66)
Castillo made his major-league debut as far back as 2018, but the 29-year-old has found work there hard to come by since, with just two innings since then, across three seasons for San Diego. A range of health problems, from a flexor strain through a middle finger issue, to the dreaded “forearm tightness”, all played their part, and he missed time last year too, appearing only once before July 9. He held opponents to a .225 average for Reno, and after becoming a free agent, re-signed with Arizona in November. According to his MLB page, his nickname is “Big Dude”, which seems a bit unimaginative. But it does list him as 6’6” and 252 pounds, so it’s not inaccurate, certainly.