Ray was part of the three-way trade that sent Didi Gregorius to the Yankees, coming to the Diamondbacks from the Tigers in December. His major-league numbers aren't good: an 8.16 ERA in six starts and three relief appearances, covering 28.2 innings for Detroit last year. His line for Reno this season has been a bit better: a 4.01 in five starts. A couple of things do stand out, which may explain why he was selected. In 24.2 innings, he has allowed only one home-run, and struck out 35 batters. That's a K-rate of 12.8 per nine innings, which is certainly impressive. Pitching in Reno could well also be good practice for Coors.
That would then make his second start the finale of the series at home against the Padres on Sunday. It seems the team are then hoping Bradley will be able to return, by the next time they need a fifth starter, which could be as far off as May 20. Ray will be 23 until October, so we probably shouldn't expect too much, but much like Rubby De La Rosa, he's a pitcher with high upside, who so far has had his share of problems converting raw stuff into consistent performances.