MIAMI -- The night got off to a bad start for the Washington Nationals -- with one of their stars on the ground, wincing in pain -- but there were some positives once the game started.
Rookie Tanner Roark pitched six scoreless innings in his first big league start, and the Nationals routed the last-place Miami Marlins, 9-2, Saturday night at Marlins Park.
Roark's performance was the silver lining for the Nats, who lost left fielder Bryce Harper to a hip injury that has been nagging him for a while.
"He aggravated it hitting," Nats manager Davey Johnson said of Harper, who was scratched from the starting lineup and replaced by Tyler Moore. "He comes and hits early, and then he takes (batting practice). Then he comes back in and hits some more.
"I think he has some inflammation in that hip. He's going to see the doctor (Sunday morning in D.C.)."
Johnson wasn't sure when Harper will rejoin the team, but the manager said his young slugger was in serious pain.
"He didn't have to tell me anything," Johnson said. "He was on the ground in the cage after he swung at a pitch.
"I was a little upset that he keeps swinging instead of just resting. He is still young and exuberant and has his own routine. Hopefully, he gets it fixed and can rejoin us in New York (for the start of a four-game series Monday against the Mets)."
Roark (5-0), a highly effective reliever since being called up Aug. 7, lowered his ERA to 0.94 after allowing four hits -- all of them singles -- and no runs. He struck out four.
The Nationals then went to their bullpen, using Ross Ohlendorf, Tyler Clippard and Drew Storen to close out the game.
Johnson said Roark has "great command" and has made quality pitches coming out of the bullpen. For that reason, Johnson was not surprised Roark continued to be effective with a sharp breaking curve ball to left-handers and a good sinker and changeup.
"He will make his next start," Johnson said with a smile. "I'm not that stupid."
The Nationals opened the scoring in the first inning by teeing off on Nate Eovaldi. After Denard Span singled, Ryan Zimmerman homered, and Jayson Werth doubled off the wall in center field, a 418-foot blast.
Marlins first baseman Logan Morrison then saved a run with a diving catch of a hard liner hit by Ian Desmond, keeping the score 2-0.
"It has to be something mechanical," Eovaldi said when asked about his poor outing. "But I'm not sure what it was."
The Nationals continued the onslaught in the third. Zimmerman led off by hitting his second homer of the game and his 19th of the season.
Catcher Wilson Ramos capped the inning with a two-run double to right. Eovaldi finished the third inning but was then removed after allowing nine hits -- four of them for extra bases -- and five runs.
"He was up in the zone, and they squared up on him pretty good," Marlins manager Mike Redmond said. "He gave up a lot of long fly balls."
The Nationals stretched their lead to 6-0 with a run in the sixth. Tyler Moore, who started in place of Harper, singled and advanced to third on Anthony Rendon's single. Moore then scored on Span's sacrifice fly.
After Werth and Adam LaRoche hit consecutive doubles in the seventh to extend Washington's lead to 7-0, the Marlins finally got on the board.
Miami got run-scoring singles in the bottom of the seventh from Adeiny Hechavarria and Jeff Mathis to cut Washington's lead to 7-2.
But Washington, which totaled 16 hits, added two more runs in the ninth on Desmond's two-run single.
"They've got guys who put the ball in the seats," Redmond said of the Nationals. "They can do some damage."
NOTES: Eovaldi is 1-2 with a 6.00 ERA in three career starts against the Nationals. ... Span extended his hitting streak to 18 games, a career high. ... Zimmerman made a spectacular first-inning play on a ground ball that took him to the right of third base. His one-hop throw to first beat Donovan Solano. ... Zimmerman has 21 career homers against the Marlins, the most he has hit against any team. ... The teams will play the deciding game of the three-game weekend series on Sunday. The Marlins will star RHP Jacob Turner, who has a 3.13 ERA -- 15th-best in the National League -- since getting called up May 3. ... The Nationals will start RHP Stephen Strasburg, who lasted just two innings in each of his past two starts against Miami. On July 12, he allowed seven runs vs. the Marlins. Then, on Aug. 28, he allowed no runs but again left after two innings because of a 72-minute rain delay.