Report: Mariners to call up their second-ranked prospect

The promotion comes only a few days after it was announced that Mariners star pitcher Robbie Ray would miss the rest of the season after having surgery on his flexor tendon. Evidently, the Mariners are looking to go with a more competitive option than depth piece Tommy Milone, who owns a career 4.59 ERA.

Miller, who is ranked as the 89th overall prospect according to MLB Pipeline, is set to face the lowly Oakland Athletics in his debut. The former Texas A&M Aggie quickly ascended the minor league ranks, moving up to AA Arkansas in his first full professional season.

Although the righty seemed to struggle with control issues in college, those concerns have been alleviated as he saw his walks per nine innings decrease drastically in affiliated ball. His BB/9 fell from 5.9 in his final year in College Station to 3.1 in 2022. 

While Miller has struggled out of the gate in 2023, posting a 6.41 ERA in 19.2 innings, Seattle believes that he has what it takes to anchor down the back of their rotation. Miller has an intimidating fastball that sits around 95 and tops out at triple digits, according to MLB.com's scouting report. He also has an above-average slider and a reliable curveball and changeup to boot.

Despite the rough start, Miller shined in his last AA start on April 25, pitching five innings of one-run ball—the only hit he allowed was a solo homer. 

Like any rookie, it might take Miller a while to settle in, but there aren't many better teams to do it against, as Oakland is ranked 25th in the league in runs scored. It remains to be seen whether Seattle will give Miller the simple spot start or an extended opportunity to stick with the team, with Milone and other top prospect Emerson Hancock waiting in the minors.

Either way, Miller looks to bring stability, and a steady dose of fastballs, to the Mariners' rotation.