Back in the major leagues since his last start nearly two weeks ago in Phoenix, Morales looks for another quality outing as the slumping Rockies (4-8) will try to snap a four-game slide.

On April 8, Morales (1-0, 1.50 ERA) gave up a run and four hits with a walk and six strikeouts a 9-2 victory over the Diamondbacks. But Morales, who was on the 60-day disabled list last season with a back injury, was optioned to Triple-A Colorado Springs after that start as the Rockies acquired right-hander Jason Hammel from Tampa Bay.

"I don't think about all that," Morales said of being sent down. "I try to do my job. It's not my decision, you know. I've got to go down and keep pitching."

He did on Wednesday in a 5-2 loss to Reno, surrendering just two hits while striking out four and walking five in six scoreless innings.

Morales is 1-1 with a 4.50 ERA in three career starts against the Diamondbacks, who are 0-5 this season against left-handed starters.

Yusmeiro Petit (0-1, 7.71) also will make his second start of the season, and his first in nearly two weeks. He'll be looking to give the Diamondbacks (5-8) their first back-to-back wins this season.

After losing to the Los Angeles Dodgers on April 11, the right-hander fared poorly in two innings of relief on April 15 in a 12-7 loss to St. Louis, giving up four runs and four hits in two innings.

Petit was to start Friday against San Francisco, but manager Bob Melvin chose to move each of his starters up one day. Petit now will make his second career start against the Rockies, and is 0-0 with a 2.57 ERA in three lifetime appearances versus them.

Arizona had scored a total of two runs while dropping two of its last three games, but broke out with a 6-3 win on Monday in the series opener. Mark Reynolds hit his third homer and drove in two while Miguel Montero had a three-run home run in the fifth inning.

That helped Montero raise his batting average 50 points, but he's still hitting just .133. Overall, the Diamondbacks are 15th in the NL with a .221 average, but Reynolds thinks Monday's effort could lead to better things.

"One guy does it, the next guy does it, and the next thing you know the whole confidence in the dugout is up," he said. "You start putting together some hits and score some runs, and I think if we do that a couple of days in a row, stuff will turn around."

After going 0-for-3 in Sunday's 2-0 loss to the Giants, second baseman Felipe Lopez had his eighth multihit game of the season for Arizona on Monday, going 2-for-5 as the Diamondbacks nearly had as many hits (10) as they did in the previous three games (11).

Lopez is batting .352.

Todd Helton went 2-for-4 in Monday's loss to raise his batting average to .231. He is 2-for-2 lifetime against Petit.