CHICAGO -- The Twins called up hard-throwing relief prospect John Curtiss on Wednesday, selecting his contract from Triple-A Rochester after designating right-hander Tim Melville for assignment on Tuesday.
Curtiss, ranked as Minnesota's No. 19 prospect by MLBPipeline.com, had eye-popping numbers in the Minors this year, posting a combined 1.28 ERA with 68 strikeouts in 49 1/3 innings between Double-A Chattanooga and Triple-A Rochester.
"The pitch selection has been good for me this year and that's mostly on the catchers calling good games," Curtiss said. "I've been commanding my slider a bit better this year, which has been a big step forward for me."
As Curtiss noted, his slider is his out pitch, but the 6-foot-4, 200-pounder also has a fastball that can reach 94-98 mph. He said his slider has improved this year because he's throwing it with the same arm speed as his fastball, fooling hitters and getting more velocity and break on his slider.
But the 24-year-old said the biggest reason for his success this year is more on the mental side than any physical or mechanical tweaks.
"I think I'm just in a calmer state of mind," Curtiss said. "My command is better. I don't think it's physical. It's more in between the ears. When I get a little too amped up, I tend to overthrow and can be out of control. When I calm myself down and not try to do too much, my command improves."
The command is still a work in progress, as he's walked 4.0 batters per nine innings this season after walking 3.7 per nine last season. But his strikeout rate has always been impressive, as he's struck out 11.3 batters per nine innings in his career, including 12.4 per nine this year.
"He's had a really nice year and the numbers kind of jump out at you," Twins manager Paul Molitor said. "You have to mindful they're Minor League numbers and all that, but he's a two-pitch guy with high-end velocity at 94-98 [mph] and a good slider. He's harnessed it and it's made a big difference in his development."
Curtiss, a sixth-round pick in the 2014 Draft, has also dealt with injury issues in the past, including Tommy John surgery while at the University of Texas, and was also shut down from throwing for two months during the 2015 season with elbow issues. But since rehabbing his elbow, he hasn't had any health scares and said he feels strong and ready to contribute at the Major League level.
"Obviously, it's a huge jump," Curtiss said. "But it's nice seeing guys like [Trevor Hildenberger] and [Alan Busenitz] come up here and be successful. It gives me confidence to follow their path."