"He threw a lot of changeups today," D-backs manager Kirk Gibson said. "He was facing a pretty good lineup today, too. They didn't bite on a lot of stuff early and made him throw his fastball."
Earlier in the day, the club optioned left-hander Tyler Skaggs to Triple-A Reno, which means the final rotation spot will go to either Delgado or Patrick Corbin.
Delgado said he is trying to focus on improving himself and is not worrying about what others are doing. On Monday, that meant using all his pitches.
"I was practicing everything -- curveball, changeup -- and I think it worked," he said.
Delgado had a shutout going through the first four innings before the Dodgers came up with a pair of runs in the fifth.
"He just kind of comes out and does what he has to do," Gibson said. "He's just trying to throw the ball better, he's trying to get more consistent with his pitches. He's close. He's close."
Steve Gilbert is a reporter for MLB.com. Follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.