CINCINNATI (AP) -- Mat Latos had only one dependable pitch. It wasn't enough.
Latos lasted only five innings because of a high pitch count, and the Washington Nationals pulled out another close game, beating the Cincinnati Reds 2-1 on Saturday night.
The Reds' biggest offseason acquisition gave up a solo homer to catcher Wilson Ramos, who left the game in the seventh inning with a significant knee injury. Latos left with the score tied at 1 after only five innings.
The right-hander gave up only three hits, but matched his career high by walking five batters, throwing 109 pitches in his brief outing.
"I didn't make the adjustment with throwing off-speed pitches," Latos said. "I threw 82 fastballs. I only had command of my fastball for the most part."
It wasn't enough.
Jordan Zimmermann (2-3) extended Washington's streak of dominant starts, giving up five hits while striking out nine in seven innings. Washington's starters have allowed one earned run or fewer 19 times this season.
Danny Espinosa hit a tiebreaking solo homer in the sixth off Jose Arredondo (2-1), his second homer in two games.
Cincinnati put Scott Rolen on the 15-day disabled list shortly before the start of the game with more pain in his left shoulder, a chronic problem the past few years. The 37-year-old third baseman had surgery on the shoulder last August.
"I called them today and said this isn't working, I'm hurting, I'm in pain," Rolen said, standing outside the clubhouse in uniform after the move was announced shortly before the start of the game. "I'm not healthy right now. As much as I want to help the team, I'm hurting the team."
Manager Dusty Baker was encouraged when Rolen hit a pair of homers and started driving the ball last month, but he tailed off again.
"You could tell he was struggling some," Baker said. "It looked like he was about to come out of it, but you could tell something was wrong by the way he was swinging. We'll rest him a couple of weeks and hope he comes out of it."
Nationals rookie Bryce Harper was back in right field with a large bandage above his left eye, covering a 10-stitch gash from slamming his bat against a wall on Friday night. He went 0 for 4 and struck out.
Manager Davey Johnson decided to leave Harper in the lineup so he could take his frustrations out on the opposing pitcher instead of the dugout wall. Instead, he ended up 0 for 9 in the series with four strikeouts.
The Reds gave away Joey Votto bobbleheads and drew 42,294 fans, their third capacity crowd of the season. For the second night in a row, Cincinnati couldn't do much against the major leagues' stingiest pitching staff.
Washington's starters have 17 quality starts in the past 18 games, taking the pressure off an offense that doesn't score a lot of runs. Zimmermann was just the latest in what's become a trend.
"He was keeping his fastball down and throwing his breaking ball in the same location, so it looked like the same pitch," Baker said. "He didn't make many mistakes, and he got strikeouts when he needed them."
Henry Rodriguez pitched the ninth for his eighth save in 10 chances, fanning three batters on 10 pitches.
The Nationals had a chance to break it open in the fifth with their young, bandaged star at the plate. The Reds intentionally walked Adam LaRoche to load the bases with two outs and bring up Harper, who hit a grounder up the middle.
Gold Glove second baseman Brandon Phillips made a backhand stop, then flipped the ball behind his back for a forceout at second, raising his arm and pounding his chest three times in celebration.
Nothing Harper could do about that.
NOTES: RH Bronson Arroyo tries for his second straight win in the final game of the series. Washington starts Edwin Jackson, who has faced the Reds only twice in his career. ... Shirley Larkin, mother of Reds SS Barry Larkin, will throw a ceremonial pitch on Sunday for Mother's Day. ... Cincinnati called up 3B Mike Costanzo from Triple-A Louisville to take Rolen's spot. Costanzo has split time between Double-A and Triple-A.
