CINCINNATI -- With no date set for Homer Bailey's return, the Cincinnati Reds could need someone to fill one more slot in the rotation. Right-hander Keyvius Sampson took the mound Saturday night eager to show he's capable of that role.

Sampson allowed one run over four-plus innings in a spot start and Jay Bruce hit a three-run homer, lifting Cincinnati to a 6-1 victory over the Arizona Diamondbacks on a steamy evening at Great American Ball Park.

Sampson allowed four hits with two walks and six strikeouts over 4 1/3 innings.

"Until we sign off on Homer ... if he's not ready to go, Keyvius did nothing to discourage us from using him in that role again," Reds manager Bryan Price said.

With trade rumors swirling, Bruce had another solid game, going 2-for-4 with a double and three RBIs.

"Nothing like a three-run homer," Price said. "It's a difference maker."

Bruce nearly had another homer in the fifth but a replay review confirmed the umpire's ruling that the ball struck the top of the wall before caroming back into play.

Prior to Saturday's game, Arizona manager Chip Hale promised retribution after Jean Segura was hit by a pitch following his leadoff homer the night before.

In the first inning, Diamondbacks starter Robbie Ray threw a breaking ball over Joey Votto's head. Intent wasn't clear and no batters were hit Saturday.

Michael Lorenzen (1-0) was awarded the victory after pitching 2 2/3 perfect innings with two strikeouts.

Ray (5-9) took the loss for Arizona despite a career-high 10 strikeouts, becoming the second pitcher in club history to fan 10 batters in five innings and the first since Max Scherzer in 2008.

Ray allowed six runs (three earned) in five innings. He only walked one batter over 105 pitches.

The Diamondbacks were held to four hits in losing their fourth straight game and 17th in the last 21 contests.

"We need to play better," manager Chip Hale said. "It's quite simple. It's not rocket science."

Cincinnati, meanwhile, improved to 6-2 since the All-Star break.

For the second straight night, Segura jumpstarted a rally in the first inning when he singled and later scored on Chris Owings' single to put Arizona ahead 1-0.

After allowing two hits, a walk and a run in the first, Sampson, who was making his first start of the season, knew he had to turn things up a notch.

"Just tried to give them what they needed after the first," Sampson said. "I needed to eat up some more innings. I was a lot more comfortable. I showed four quality pitches. I'd like them to think there's a bit of a starter in (me)."

Cincinnati took the lead in the bottom half when with runners on second and third, third baseman Jake Lamb's throwing error on Adam Duvall's grounder allowed two runs to score.

Brandon Phillips' double to right drove home Duvall to make it 3-1.

Ray needed 34 pitches to get through the first inning.

After striking out the side in the second, Ray got pounded in the third when Bruce followed back-to-back singles with his 20th homer of the season, making it 6-1.

Bruce's bomb came on an 0-2 pitch.

"I should never give up an 0-2 hit, much less a homer, to a left-hander," Ray said. "I tried to bury a slider and left it up and over the plate."

Sampson left with a 1-0 count on Michael Bourn in the fifth inning.

"He muscled up on the pitch before and the next one was an elevation pitch," Price said. "I talked it over with (pitching coach) Mack Jenkins and we decided to get him out of there."

Sampson threw 88 pitches, three more than limit set for him.

Lorenzen relieved Sampson and was credited with a strikeout of Bourn.

"As a team, we're not playing well enough," Arizona first baseman Paul Goldschmidt said. "The last two nights, it's been the offense."

NOTES: The Diamondbacks reinstated SS Chris Owings (foot) from the 15-day disabled list and placed INF Nick Ahmed on the 15-day DL because of a right hip impingement. ... Owings started at shortstop and batted fifth. ... Reds RHP Tim Adleman made his third rehab start Thursday for Triple-A Louisville. Adleman could be an option to start for Cincinnati depending on how RHP Homer Bailey comes through his sixth rehab outing Monday. ... The first inning lasted 38 minutes and had a combined 61 pitches. ... John Travolta and wife Kelly Preston attended Saturday's game. They are filming a movie in Cincinnati.