Webb (11-4, 3.23 ERA) started the season 9-0, but is 2-4 with a 4.22 ERA in seven starts since then. He gave up five runs in seven innings of Sunday's 5-3 loss at Minnesota, five days after yielding seven runs in 3 1-3 innings against Oakland in his shortest outing since 2004.

"It seems like the big inning has been the problem," the 2006 NL Cy Young Award-winner said. "If it's one or two, it's not as big of a deal. But four or five runs in one inning is a bad inning. I need to cut down and try to minimize the damage."

Despite his recent slump, Webb still leads the NL in wins. The Diamondbacks (40-40) could certainly use a strong outing from him, as they have dropped six of their last seven games to fall back to .500 for the first time since they were 2-2.

Arizona lost 3-1 in Friday's opener, falling to 0-4 against Florida (41-38) this season. The Diamondbacks have managed only four runs against the Marlins while allowing 13.

Orlando Hudson hit a sacrifice fly in the first inning, driving in Arizona's only run. The Diamondbacks have scored three or fewer runs in 11 of 13 games.

"We're playing like dog crap out there," third baseman Mark Reynolds said. "Right now, we got to make things happen. We've got to swing the bats better. We got off to a good start tonight, and then we just shut it down."

Webb is 3-4 with a 4.85 ERA in seven career starts against the Marlins. He went seven innings and allowed three runs on May 21 in Florida, but was charged with a 3-1 loss, ending a three-start winning streak against the Marlins.

"It's not a time frame for us to feel sorry for ourselves," said starter Micah Owings, who was charged with Friday's loss. "It's time for us to dig a little deeper and pick each other up and keep working."

The Marlins, who snapped a four-game losing streak Friday, have also struggled to score runs lately, managing fewer than four for the fourth time in five games.

However, starter Ricky Nolasco picked up his teammates with eight strong innings.

"That was the most important thing today was to snap that losing streak and get on the right page again," Nolasco said. "We had a rough stretch of games there."

Now, Andrew Miller (5-6, 5.07) will try to give the Marlins another solid start. The left-hander, 1-3 with a 4.65 ERA over his last six starts, gave up five runs in four innings of Sunday's 7-1 loss in Oakland.

"That's disappointing to go out there when the series is 1-1, and you hope to go out there and pitch well," he told the Marlins' official team Web site. "I didn't do that."

Miller made his only previous start against Arizona on May 22, throwing seven innings opposite Dan Haren in a 4-0 home win.