Mantiply struck out one in a scoreless two-thirds of an inning to record his first save of the season in Wednesday's 4-3 win over the Reds.
Mantiply (1-0) picked up Wednesday's win over Colorado, retiring the lone batter faced in the eighth inning.
Mantiply allowed a walk over a scoreless inning in Friday's 6-5 extra-inning loss to Atlanta.
Mantiply allowed one hit and hit two batters over a scoreless inning in Friday's spring game against Cincinnati.
Mantiply will start Sunday's game against the Cubs, Steve Gilbert of MLB.com reports.
Mantiply is scheduled to work as the Diamondbacks' opening pitcher for Monday's game against the Rangers, Jody Jackson of Bally Sports Arizona reports.
Mantiply will serve as the Diamondbacks' opening pitcher for Tuesday's game in Colorado, Jody Jackson of Bally Sports Arizona reports.
Mantiply (1-1) was charged with Monday's loss to the Rockies. He allowed three runs on three hits and did not retire a batter.
The Diamondbacks recalled Mantiply from Triple-A Reno on Tuesday, Alex Weiner of ArizonaSports.com reports.
Mantiply was optioned to Triple-A Reno on Friday.