Curtis, who is in his third professional season, appeared in eight games for the Rawhide this season. The 23-year-old was 1-0 with a 5.23 ERA and 22 strikeouts in 10 1/3 innings, while recording two saves. Curtis has been particularly effective against left-handed hitters -- they are hitting just 3-for-14 (.214) against him. He joined the bullpen to help lighten the pitching load for left-handed specialist Andrew Chafin.
"We'll use him probably earlier in the game to get a lefty," D-backs manager Chip Hale said. "He's pitched multiple innings, so we won't be afraid if we need to leave him in there for a couple of innings."
Curtis, who visited Chase Field for the first time Saturday, was told about his promotion Friday night. He initially thought he was going to Double-A and could not believe the news when he was told that he was joining the big league team in Phoenix. The pitcher said one of the biggest thrills so far was telling his wife Chelsea about the promotion. The couple have a two-year-old son named Greyson.
"It's a funny feeling," Curtis said before Saturday's debut. "I don't know if I'll be as nervous as anxious. I told someone else in the outfield that I kind of have the same feeling now as I did when I got called up from Low-A to High-A for the playoffs. As soon as I delivered the first pitch, it kind of settled in. I think that's the only nerves I'll have. I won't be nervous."
A sixth-round pick by the D-backs in the 2014 Draft out of Middle Tennessee State, Curtis was named a Midwest League midseason All-Star in 2015, when he recorded a 1.33 ERA in 54 innings.
Hessler pitched three innings for the D-backs this year, allowing three runs on five hits, while striking out two.
"You look at his numbers and he's done a really nice job," Hale said. "He's had a couple of bad outings this year."
Jesse Sanchez is a national reporter for MLB.com based in Phoenix. Follow him on Twitter @JesseSanchezMLB and Facebook. This story was not subject to the approval of Major League Baseball or its clubs.