Davey Johnson isn't looking forward to the end of Jordan Zimmermann's season.

The Washington Nationals' manager has enjoyed his right-hander's comeback from 2009 Tommy John surgery, but now Johnson knows that Zimmermann has just two starts left.

At the beginning of the season, the Nationals decided to limit Zimmermann to 160 innings, and after Thursday night's 3-1 win over the Cincinnati Reds, he's pitched 150 2-3.

But before the game, Johnson and Washington General Manager Mike Rizzo decided the preseason quota could be exceeded, if slightly.

Will it be hard for Johnson to shut Zimmermann down?

"No question about it," Johnson said. "I got two more starts out of him."

Zimmermann and four relievers combined to limit the Reds to an unearned run. Zimmermann (8-10) allowed six hits, walking one and striking out two. He left with runners on first and second and two outs in the sixth.

"I told him after the game, 'Don't make me have to come out there. You've got unfinished business out there,'" Johnson said. "I don't like to do it. He's too good a pitcher."

Ryan Mattheus came on to strike out Paul Janish to end the inning. Mattheus did not face another batter because of a tight right shoulder.

The Reds scored the unearned run in the seventh off Henry Rodriguez. Tyler Clippard pitched a scoreless eighth and Drew Storen worked the ninth for his 33rd save in 37 chances.

"I don't know how it's going to be," Zimmermann said. "I'm going to keep pitching until they tell me to stop — one or two more starts — I'm not sure. I watched for a whole year. I think I can handle a month."

Zimmermann's start came the day before the two-year anniversary of the surgery, but he didn't mention it after the game.

"It was getting pretty late, and I was getting pretty tired toward the end there," Zimmermann said. "I want to stay out there 120 pitches if I can. I know it's still early in the Tommy John process. You've got to keep the pitches down."

Zimmermann had help from former Red Jonny Gomes, who had a two-run single and a running catch that ended with him banging into the left field wall, and his catcher, Jesus Flores, who hit his first home run in more than two years.

Gomes, who was traded to the Nationals by the Reds on July 26, drove in two runs in the bottom of the sixth on a single to left. He also made a nice running catch on a flyball by Joey Votto to end the fifth inning, slamming into the wall in left after making the grab.

"I was a little worried he might have hurt the wall," Johnson joked.

Gomes insisted he didn't have extra incentive because Cincinnati traded him.

"It's not like we took two out of three from the Reds, and now my season's over," Gomes said.

Flores homered to left field with one out in the fifth off Bronson Arroyo (7-10). It was the catcher's first homer since May 8, 2009. Flores missed most of the 2009 and all of last season after undergoing surgery on his right shoulder.

Arroyo, who hasn't won in his last nine starts, pitched six innings, giving up three runs and seven hits. He's worked at least six innings in his last eight starts.

"Jonny made us pay for it, and that's why we got a loss," Arroyo said.

In the seventh, Fred Lewis led off with a grounder to short that was booted by Ian Desmond. He moved to second on a wild pitch by Rodriguez and to third on Flores' passed ball. He scored on Brandon Phillips' infield out.

Ryan Hanigan, who had a season-high four hits, and Phillips, who had three, had seven of Cincinnati's eight hits.

NOTES: Bryce Harper, the No. 1 overall pick in the 2010 draft by Washington, injured his right hamstring during Double-A Harrisburg's 4-2 victory at Akron. Harper was injured running to third base in the eighth inning and was replaced by a pinch runner. The Nationals announced Thursday night that Harper had a right hamstring strain and would be reevaluated on Friday. ... Johnson said he wasn't worried about RHP Stephen Strasburg, who allowed five runs in 1 2-3 innings for Class-A Hagerstown on Wednesday. "He's not worried about pitching to hitters — setting them up," Johnson said. "He's worried about throwing pitches — his release point — his rhythm. He's not concerned about results." Strasburg, who is rehabbing from Tommy John surgery, will pitch again next Monday for Hagerstown. ... The game's start was delayed by 32 minutes. ... Reds OF Jay Bruce was named the NL's Player of the Week for the second time this season. He went 0 for 4. ... Cincinnati SS Edgar Renteria missed his second straight game with a strained left groin. ... The Nationals introduced their recently signed third-round draft choice LHP Matt Purke and said he would report to Viera, Fla., in a few days to be evaluated. ... Washington begins a three-game series with Philadelphia on Friday night. RHP Livan Hernandez (7-11) will face RHP Roy Oswalt (5-7). Hernandez has 13 wins against the Phillies — more than any active pitcher. ... The Reds travel to Pittsburgh to begin a three-game series. RHP Homer Bailey (7-5) is scheduled to face RHP Kevin Correia (12-11).