The Cincinnati Reds and Arizona Diamondbacks are both struggling offensively, and their star hitters are at the forefront of those slumps.

They'll look for Todd Frazier and Paul Goldschmidt to turn things around as they open a three-game series in Phoenix on Friday night.

Cincinnati (48-58) is scoreless over its last 18 innings and shut out twice while dropping three of its last four games after being five-hit in Thursday's 3-0 loss to St. Louis. Frazier stayed cold, going 0 for 4 to fall to 4 for 40 with 12 strikeouts over his last 10 games.

More from FoxSports

"I'm swinging at pitches I should be hitting, fouling balls off, I'm not really squaring them up," he told MLB's official website. "You go through it during the year. It's just a matter of how long it's going to go for."

The Reds have averaged 5.4 runs while winning 16 of 21 at Chase Field, though Frazier's hitting .229 in 10 games there.

While Cincinnati is opening a 10-game trip, the Diamondbacks (52-55) lost four of six to end one of their own after starting it 4-0. They totaled 10 runs in the four losses.

Goldschmidt, who was hitless in four straight games before going 3 for 5 Wednesday at Washington, got his first day off this season in Thursday's 8-3 defeat.

This matchup features two rookie starters seeking firsts.

Arizona's Robbie Ray (3-6, 3.01 ERA) is looking for his first home win, and to achieve it, he'll likely need to perform better with runners in scoring position. The left-hander limited opponents to a .167 batting average in those situations through his first nine games, but they've gone 5 for 12 in his last three.

"It's just tough when you've got guys on base and you're in those high-pressure situations all the time," he said. "Eventually, it's going to catch up to you."

The matchup could favor Frazier, whose .973 OPS against lefties is the highest by a Red since Joey Votto's .987 mark in 2011.

After recording his first victory in six starts, Raisel Iglesias (2-3, 5.13) looks to win consecutive outings for the first time. He threw 6 2-3 innings - his second-most - while limiting Pittsburgh to two runs and four hits in Saturday's 4-3 home victory.

"I'm very happy, I'm excited that I helped the team to win, especially that I went a little bit deeper in the game today," he said through a translator. "I'm very thankful to my teammates because they played a really good game for me, and I just went out there and did my job."

Iglesias will have to overcome his road difficulties, going 0-3 with a 8.16 ERA and opponents hitting .333. At home, he's limited opponents to a .238 average.

The right-hander has also had problems with home runs lately, allowing exactly one in five straight outings after not being taken deep in his first five appearances.

Cincinnati won last season's series 4-3 powered by Devin Mesoraco's four homers and nine RBIs. Mesoraco, though, had season-ending hip surgery in May.

Goldschmidt went 4 for 27 with 10 strikeouts against the Reds last year.