Keller struck out 10 batters in five shutout innings for Low-A West Virginia on Friday.
The 20-year-old has yet to give up a run in 15 innings, striking out 23 batters. Keller generates plenty of swing-and-miss at-bats with a mid 90s fastball. He's a couple of years away from making a possible big-league debut, but fantasy owners in keeper leagues might want to track his progress.