Martinez is a cool story -- he was an 18th round pick of the Rangers in 2011 out of Fordham, where he was an infielder, but the Rangers drafted him as a pitcher and converted him to the mound. He ended up making the Opening Day roster in the Rangers’ ill-fated 2014 season, bounced between AAA and the big leagues the next several years, and ended up logging 415 innings from 2014-17 in the majors for Texas, working mostly as a starter, but also doing some work out of the pen.
Martinez had a 4.77 ERA and a 5.36 FIP in the majors, and while he wasn’t spectacular, he was a useful swingman who provided needed rotation depth. Martinez was out of options after the 2017 season, which reduced his value (since he couldn’t be shuttled back and forth between the majors and minors as needed), and the Rangers opted to non-tender him, making him a free agent.
Best of luck to Martinez with the Ham Fighters, and hopefully we see him back in the majors at some point in the future.