The Pirates optioned Keller to Triple-A Indianapolis on Saturday.
The Pirates' top pitching prospect always looked destined to open 2019 in the minors with the front office only considering Jordan Lyles, Steven Brault and Nick Kingham for the final spot in the Opening Day rotation. None of the trio will be assured a starting gig all season, however, so Keller could easily push his way into the Pirates' rotation plans with a strong showing at Triple-A early on. The 22-year-old had a rough go of the International League in 2018, supplying a 4.82 ERA and 1.55 WHIP across 10 starts.