MIAMI -- Giants left-hander Madison Bumgarner knew it would be one of those outings when he began warming up prior to Wednesday's 4-2 loss to the Marlins at Marlins Park.

In the midst of a skid, it couldn't have come at a more inopportune time for the Giants, who turned to their ace in the hopes of putting a stop to it.

Through six innings, Bumgarner did his part. But Giants manager Bruce Bochy took the ball from his workhorse in the decisive seventh after Jorge Alfaro's third hit -- a leadoff single -- en route to San Francisco’s season-long seventh straight defeat.

• Box score

Bumgarner, who was seen chatting with Bochy in the dugout afterward, had thrown just 81 pitches with the eighth batter in the lineup due up in a 1-1 game. However, he needed 56 pitches to get through the first three innings, including 27 in the third, and that proved taxing.

"I think it was one of those days," said Bumgarner, who allowed two runs over six-plus innings. "With our bullpen as good as they are, just felt like that was the best thing. I back him up on that. Don't really have a reason for [tiring], wish I did. There's just certain times throughout the year where you feel really good and sometimes where you don't. And then a bunch of average ones."

Right-hander Mark Melancon came on in relief and got Miguel Rojas for the first out before pinch-hitter Curtis Granderson singled to put runners at the corners. Pinch-hitter Neil Walker, a former teammate of Melancon's in Pittsburgh, followed with the go-ahead RBI double and Garrett Cooper added a sacrifice fly to right.

"We had talked," Bochy said of the decision to pull Bumgarner. "Every day's different when you pitch. He was gassed from the third inning on. Every start's a little bit different, and we were going to hit [for him in the sixth but] we didn't get somebody on. I let him start it and said, 'I've got you covered.'

"What he's done, I should cover him there. He was so gassed the third inning on. I brought in a good reliever, and they had some good at-bats. That's a tough one, no question. As you know, it hasn't happened a lot, but occasionally it has, where I have to take care of a starter when he's feeling it a little bit."

And Bochy did turn to a hot hand in the bullpen. Melancon entered the game with six consecutive scoreless outings, with one walk and seven strikeouts. Miami tacked on another run against reliever Sam Dyson in the eighth.

It falls in line with how things are going for the Giants.

"We're not having a lot of luck here right now -- not that you look for luck," Bochy said. "We get a big out, and the way Mark's been throwing the ball, you certainly like your chances getting out of that inning. Got a couple of big hits there."

Despite how he felt, Bumgarner did give the Giants their first quality start since his outing last Thursday against the Braves. He scattered six hits with one intentional walk and four strikeouts.

Bumgarner, who entered the game 10th in the National League in innings, still managed to provide length by finding a groove in the middle frames. He did not permit a baserunner in the fifth or sixth.

"Sometimes you know you might have to get deeper into the game, and today was one of those days where I really felt like I should have, and I wanted to, but at the same time, we're trying to win any way we can, so I've got to do whatever we think is best for the team," Bumgarner said. "Just didn't work out today."