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4/12/2014 8:11 P.M. ET

Collmenter aims to stay in rotation

PHOENIX -- Josh Collmenter is back in the starting rotation and he intends to stay there.

"I take it in stride and I'll do whatever I can with the team to help out," Collmenter said. "It's obviously nice to come back to the rotation. It's something not a whole lot of guys get to do once they are sent to the bullpen. To be able to go back and forth really helps out."

Collmenter, who has not started a game for the D-backs since 2012, will make his season debut as starter against the Mets on Monday. He's allowed two runs in eight innings during four appearances out of the bullpen this season.

"I've done it plenty of times so it's not a big deal," Collmenter said. "Preparation is pretty much the exact same. Any time I go out there I usually get to throw multiple innings. Now, I just know the exact day I'm going to pitch. It's really the only thing that changes."

Collmenter made 11 starts for the D-backs in 2012 but his best year as a starter came in 2011 when he went 10-10 with a 3.38 ERA in 24 starts. He has relied heavily on his fastball and changeup but might have to incorporate his curveball more to keep hitters off balance.

He threw four innings of relief against the Giants in his last outing to help prepare him for the shift. He expects to throw 90 pitches Monday.

"Everything is pretty much scripted [as a starter] and you know exactly when you are going to throw," he said. "The bullpen is fun because you get that burst of adrenaline, but it's definitely fun to have both sides of the coin and know how to do both. "

The D-backs made room in the rotation for Collmenter by moving Randall Delgado to the bullpen. Delgado lasted just 3 1/3 innings in his start Thursday night. He pitched only four innings against the Rockies in the previous start.

"We just didn't feel Randall in his starts was improving," D-backs manager Kirk Gibson said. "He was having a hard time with his third pitch, which is his curveball, and I just felt team-wise we needed to get more length out of our starting pitchers and we didn't see that happening soon enough with Randall and at the same time, we thought Randall might benefit from going to the bullpen where there's not so much pressure of going through the lineup three times."

As for Collmenter, he's 1-1 with a 4.50 ERA in six appearances/one start in 18 career innings against the Mets.

"Who knows for how long, but I want to be a part of this rotation and hopefully, get things turned around here," he said.

D-backs giving Cahill time to improve

PHOENIX -- The D-backs are standing behind starter Trevor Cahill.

Cahill, who allowed five runs in 3 1/3 innings against the Giants in his last start, is scheduled to take the mound Sunday against the Dodgers in the series finale. D-backs manager Kirk Gibson downplayed the notion that Sunday's start is a "make-or-break" outing for Cahill when he was asked.

"We are all confident Trevor has good stuff and he can apply it," Gibson said. "He's been really good about being open to suggestions. He really hasn't been as consistent as he wants to yet. I think we are doing things a little bit different this year so it's been a lot for him to handle."

Cahill, who was acquired from the A's in a trade in 2011, has pitched a total of 13 2/3 innings in this three starts this season. He is being paid $7.7 million for this season and is owed $12 million for 2015.

"I just have to trust my stuff and see what happens," Cahill said. "If I was 6-0 and had a couple of bad starts it would not be as big of a deal, but I had a bad spring and that didn't help, either. It is what is. I'm not going to be a different person. I'm going to continue to work hard and go out there and do my best. It's all I can do."

The D-backs would like Cahill to simplify his approach on the mound and avoid overanalyzing situations. The club would also like the pitcher to aware of his pace during games, maintain a good tempo and "throw his pitches with conviction."

"We just see him repeating his delivery more and making progress," Gibson said. "You guys have seen him throw some great games, but we need to see him do that consistently and give us a chance to win ballgames."

Perez living his dream playing in Arizona

PHOENIX -- D-backs reliever Oliver Perez can't remember being in a better situation as a professional ballplayer.

"It's really been a dream come true to play here in Arizona, especially when you think about playing your entire career away from home," Perez said. "I played in the winter in Culiacan, Mexico, my home, and that was the best and now I'm here not far from where I live."

Perez has seen better days on the mound but he remains optimistic. He's given up four hits and six runs -- five earned -- in his first seven appearances of the season. Perez has struck out two batters and walked four.

"We've struggled a little bit but we know this is a long season and there are ups and downs," Perez said. "Personally, I feel fine. I had a tough little stretch, but that happens to everyone and we are all working to get better. Things will get better."

Jesse Sanchez is a national reporter for MLB.com. Follow him on Twitter @JesseSanchezMLB. This story was not subject to the approval of Major League Baseball or its clubs.