Trent Thornton is the 24th ranked prospect of the Houston Astros according to MLB Pipeline. He is 25-years-old, a former 5th round pick out of UNC, and blocked in a deep Astros system. The Astros have used him as a starter almost his entire career making 78 minor league starts. He has a 1.71 BB/9 in his career to go with a 7.96 K/9. His ERA is 4.23 while his WHIP is just 1.25. His FIP for 2018 was 4.01 and his xFIP was 3.93. For the previous year his ERA was 5.09, his FIP was 4.28, and his xFIP was 4.24. And if you keep going back for each level he has pitched at, you will see this type of setup. His BABIP was .304 last year and .338 the year before. This all suggests that he should be getting better results than he is.
On April 23, Thornton struck out eight consecutive batters against Reno tying a PCL record. On June 16, Thornton took a no-hitter into the 8th inning before losing it with two outs. These are just two highlights from a solid 2018 season.
Thornton was 93-95 last season and can get up past 96 on occasion. He throws a curve, slider, and change. The curve has a power type break that is late and hard. It isn’t a big breaker, but a short, tight, 12-6 break. His slider is a lot like a cutter but moves more. There is some sink but it just darts off the edge of the plate.
Thornton has a big leg kick that goes with a herky jerky motion. He has a stabbing arm action that comes from a high glove. He doesn’t lift his hands over his head, but he lifts them back by his ear and above his head when he lifts his leg. It’s unusual, but it works for him.

This picture of Thornton from UNC shows the leg kick and the high glove placement prior to his arm action and delivery.
Some people project him to be a reliever because of the arm motion and some project him to be a number 4 or 5 because of the stuff. I’m not sure where the best fit for him would be but he could probably pitch out of a big league pen right now. If I’m the Royals, I trade for him now and give him a shot in the rotation this spring with a fall back of the bullpen. If he doesn’t make the big league team, you put him in the rotation in Omaha and go from there.
Here is where it gets complicated. Thornton is Rule 5 eligible this year as a college signing. If the Royals traded for him, they would have to protect him by placing him on the 40-man roster almost immediately. Currently, there are 43 players on the 40-man with 4 on the 60-day DL. Hammel will be one of those guys so let’s say 42 players on the 40-man. Where are you going to put him? If you traded for him now instead of taking him in the Rule 5 draft, you can put him in the minors and use up some options instead of having to keep him on the 25-man roster. Keep in mind, the Royals pick 2nd in the Rule 5 so they will probably be selecting and keeping a player for the full season. Perhaps you offer cash considerations or international bonus money because the Astros will probably be losing Thornton for $50,000 if they don’t protect him. Thornton is a solid arm that should be a good and cheap option for the Royals.
Pictures from UNC website and MILB.com.