PITTSBURGH -- Edinson Volquez was aggressive, Gregory Polanco was patient and it added up to a Pittsburgh Pirates' victory.

Volquez continued his mastery of the Miami Marlins, allowing one hit in seven scoreless innings, and Polanco, the rookie right fielder, drove in four runs in the Pirates' 7-2 win Thursday night.

The lone hit off Volquez was a fifth-inning single by infielder Donovan Solano, who was subbing for slumping third baseman Casey McGehee.

The right-hander improved to 6-0 with a 1.64 ERA in seven career starts against the Marlins. He struck out seven and walked three as he won for the first time in four starts since the All-Star break after winning his last four starts of the first half.

"Tonight was one of the best nights I've had with my fastball," Volquez said. "It was great for me because I was able to keep the ball down and get a lot of ground balls. I was trying to get ahead in the count the whole time and be aggressive in the strike zone."

Conversely, Polanco got ahead in the count 2-0 before hitting a two-run opposite-field single to left field off rookie left-hander Brian Flynn (0-1) that capped three-run fourth inning that broke a scoreless tie.

Polanco also hit a two-run double in the eighth off closer Steve Cishek, who was getting in some work after having not pitched since last Saturday, to make it 7-0.

"I think that's the third time he's shown that ability to hit a ball into left field off a left-hander so far this season and just to stay on the ball and not try and get outside himself," Pirates manager Clint Hurdle said. "Take what they're giving him. When they're throwing down and away, he stayed out over the plate and covered it."

The Marlins had a scary moment in the seventh inning when Pirates shortstop Jordy Mercer hit a line drive off the right side of left-handed reliever Dan Jennings' head. The ball struck Jennings with such force that it popped into the air and was caught behind second base by shortstop Adeiny Hechavarria.

Jennings tried to get to his feet but fell to his knees and was attended to by athletic trainers from both teams. He raised his hand to the crowd while being taken off the field on a cart and drew a loud ovation.

Jennings was taken to a local hospital for observation.

"It's definitely scary," Marlins catcher Jarrod Saltalamacchia said. "I'd never been on the field when that happened. It goes past baseball. You start thinking about life. He has a wife and a kid."

Mercer was also shaken by the incident.

"You watch it unfold and you hope he gets up," he said. "You don't want anything like that. I had the best seat in the house and it wasn't pretty."

Right fielder Giancarlo Stanton hit his National League-leading 27th home run, a two-out shot off rookie right-hander Stolmy Pimentel, with two outs in the ninth inning to keep the Marlins from being shut out.

Mercer had three hits, including a double to lead off a three-run fourth inning that broke a scoreless tie, and a single during a two-run fifth that extended the Pirates' lead to 5-0.

Polanco, catcher Russell Martin and center fielder Starling Marte had two hits apiece. Martin extended his hitting streak to six games.

NOTES: Pirates CF Andrew McCutchen missed his third consecutive game with a fracture in his lower left ribcage. Manager Clint Hurdle said there is a chance McCutchen could avoid going on the disabled list. ... Pittsburgh 2B Neil Walker sat out for the fourth time in five games because of lower back tightness. He felt better after getting treatment prior to Thursday night's game but likely won't return to the lineup until Saturday. ... Marlins 3B Casey McGehee did not start for the just the second time in 113 games this season. He entered the day in a 7-for-54 (.130) slump, and he was 0-for-8 in his career against Pirates RHP Edinson Volquez, who started. ... Miami RHP Nathan Eovaldi (5-6, 4.22 ERA) will pitch against Reds RHP Mike Leake (9-9, 3.46) on Friday at Cincinnati in the opener of a three-game series. ... The Pirates begin a three-game home series against the Padres on Friday with Pittsburgh RHP Vance Worley (4-1, 2.43) facing San Diego RHP Ian Kennedy (8-9, 3.59).