Anybody who makes the jump from Double-A to the major leagues in one season deserves to be on a list like this and Graterol has been no exception. Although the right-hander missed over two months with a shoulder impingement, his season has been impressive enough for the Twins to believe he can be an asset in their run to the postseason.
Graterol had already achieved top prospect status prior to this season, as he cruised through Low-A Cedar Rapids and High-A Fort Myers with an 8-4 record and 2.74 ERA in 102 innings. The Twins would start him at Double-A Pensacola this season and the 21-year old was unfazed, going 5-0 with a 1.89 ERA prior to the injury.
After coming back in July, the Twins opted to try him out as a reliever and he quickly made his way through Pensacola and Triple-A Rochester before making his major league debut this month.
Although his results at the major league level have been spotty (4 ER in 8 1/3 innings), he’s shown enough to remain one of the top prospects in the organization. In all likelihood, the Twins will start Graterol at Triple-A in 2020 to get used to starting again and could call him up at the first sign of trouble in the rotation.