Kirk Gibson must monitor Patrick Corbin closely if he wants Arizona to reach the playoffs.
Kirk Gibson must monitor Patrick Corbin closely if he wants Arizona to reach the playoffs. (USATSI)

NEW YORK -- The National League West is forgiving.

The Diamondbacks have lost five in a row and eight out of nine. Not only are they still in first place, but they've lost only a game and a half off their lead during that slide.

It's easy to pick apart this team, easy to say that they're 12 games under .500 when they start anyone other than Patrick Corbin. The rest of the rotation behind Corbin has a 4.76 ERA, which would rank 14th among the 15 National League teams (only the Brewers have been worse).

But then you remember that the Diamondbacks are still a first-place team, even after another ugly loss on Tuesday night, 9-1 to the Mets. They're still a first-place team, even though they don't have a win from a starting pitcher since June 5, even though they have as many blown saves as any team in the major leagues.

"Things are being cruel to us now," manager Kirk Gibson said, even before Tuesday's loss. "That's OK. We accept the challenge."

They're still in first place, this is still the National League West, and somebody is going to win this division. The question is how they do it.

Two keys:

1.) They need to find a way to keep the 23-year-old Corbin strong through the second half though he is on pace to throw far more innings than he ever has.

2.) They need to find a way to get their other starters to help him out.

Corbin has been brilliant. He wasn't even bad Tuesday, though the box score shows he allowed five runs in six innings-plus. The truth is that he made one bad pitch/bad decision in the first six innings, a two-out changeup that Anthony Recker hit for a home run. Then he allowed the first four Mets to reach base in the rain-soaked seventh inning and, eventually (after a long rain delay), all of them scored.

It went down as his first loss and as just the Diamondbacks' second loss in his 17 starts.

Without him, they're nowhere near first place, though he began the season as their fifth starter.

"I'll take him against anyone in the league," closer J.J. Putz said. "He's been a horse. Ride that horse."

They have, and Corbin has already thrown 115 2/3 innings, with the Diamondbacks just two games past the midway point of the season. He threw 186 1/3 innings last season (majors and minors combined), and even then he was tired enough at the end that it contributed to a 6.03 September ERA.

Gibson brought up the workload on Tuesday, before he could even be asked about it. He acknowledges it could be an issue, and he knows how much the Diamondbacks have relied on Corbin.

He said they'll probably give Corbin as long of an All-Star break as they can, slotting him in fifth after the break. He points out that he hasn't allowed Corbin to run up high pitch counts (his highest in a game this season is just 111).

Corbin has been efficient with his pitches. While he came into Tuesday 10th in the majors in innings, he was only 58th in number of pitches thrown.

"I hope he gets to pitch 260 innings this year," Gibson said, knowing that would mean a long postseason run.

"I feel fine," Corbin said. "I'm ready to go out and throw as many innings as I can."

For that to matter, the rest of the rotation will need to improve. Maybe that comes through a trade, though general manager Kevin Towers told the Arizona Republic that "we're not going to rush into anything."

Towers said he doesn't see trading for a middle-of-the-rotation answer, so it might be that he won't find what he needs on the market.

Perhaps the Diamondbacks can find another answer from their system, another Corbin (maybe Tyler Skaggs, maybe even Archie Bradley). Maybe some of the other starters in the rotation improve.

"We've just been inconsistent," pitching coach Charles Nagy said.

They've been worse than that lately. The 24-game streak without a win from a starter can be blamed partly on the unreliable bullpen and partly on the inconsistent offense, but the starting pitchers have a 5.04 ERA in that span.

Take out Corbin's six starts, and the rotation ERA since June 5 soars to 5.83.

That's obviously not good enough for a team that intends to win. It normally wouldn't be good enough to keep a team in first place.

This is the NL West, though, so the question is less how the Diamondbacks have managed to stay on top than it is how they can find a way to stay there the rest of the season.

Keeping Corbin strong has to be a big part of the answer.