CINCINNATI -- Left-hander Jorge De La Rosa has made two starts since returning from a finger injury, but the Rockies are still waiting for his comeback.

De La Rosa gave up seven runs and three home runs -- two by Drew Stubbs and a three-run Brandon Phillips homer -- and walked five in 3 1/3 innings. The result was an 8-1 loss to the National League Central-leading Reds at Great American Ball Park on Saturday.

De La Rosa (3-2), who spent 2 1/2 months on the 15-day disabled list with a torn sheath of a tendon in his left middle finger, also struggled in his return start, giving up seven runs (five earned) in 4 1/3 innings on July 9 against the Padres. The Rockies came back and won that game, however.

"We weren't given much of a chance to get ourselves completely involved in the game, because we didn't pitch well at all," Rockies manager Jim Tracy said.

The Rockies, who began the night second in the NL West, need the De La Rosa who was 19-4 from last June until suffering the injury on April 25. Tracy didn't indicate panic but noted that "the timeframe is not a real large one" since the Rockies are in the second half of the season.

De La Rosa said he'll search for answers on the video, but otherwise will focus on his next start.

"I can pitch better than that, and I will be better than that because I'll keep working hard and try to help my team," De La Rosa said. "I'm not going to put pressure on myself. I've just got to go out there and throw my game. That's going to happen."

Reds manager Dusty Baker said there were signs of the old De La Rosa, but all that disappeared with Stubbs' two-run homer in the second.

"He got us on the board because that guy was tough early," Baker said. "He was sinking the ball out of the zone, and we were chasing him some, but then we got a little more patient and Stubbs got us on the board."

The Reds, who also had a fifth-inning leadoff homer from Jonny Gomes off reliever Jhoulys Chacin, basked in a feel-good comeback story.

Edinson Volquez (1-0), back from Tommy John right elbow ligament transfer surgery and on a Major League mound for the first time since June 1, 2009, struck out nine and held the Rockies to one run and three hits in six innings.

Volquez displayed an effective fastball, and confounded the Rockies with his changeup and other secondary pitches.

"We heard some good things from the games he's pitched already, coming back in the Minor Leagues," Rockies shortstop Clint Barmes said. "We thought he might have, possibly, some control problems being at this level for the first time in a while. But he threw the ball extremely well."

The Rockies gave De La Rosa a 1-0 lead. Dexter Fowler opened the first with a double and scored on Carlos Gonzalez's one-out single. Gonzalez stole second shortly after the hit. After that, no Rockies player reached second base against Volquez.

De La Rosa pitched the Rockies into a hole, but the offense was absent again. The Rockies lost Friday night's game, 3-2, after blowing a bases-loaded, no-outs chance in the eighth. Jonathan Herrera has a 13-game hit streak, and Gonzalez improved his streak to 10, but the Rockies need more to recapture the production that helped them to an 8-2 homestand to finish the pre-All-Star break schedule.

"We're still in a wonderful position," Tracy said. "But the motor's got to start running."