If you just watched the first two innings of Luke Weaver's start against the Marlins on Wednesday night, you could understand if the D-backs decided to take the right-hander out of their rotation.

But if you only watched the second two innings of his outing, you would understand why it's not an easy decision. Because when his stuff is working, when he's able to locate his fastball, he is a force to be reckoned with.

When he's not, however, opposing teams make him pay for it. That's what the Marlins did as they scored six runs in the first two innings, rolling past the D-backs, 8-0, at loanDepot park.

• Box score

"When it’s good, it’s real good," D-backs manager Torey Lovullo said. "He can spoil us. We just want more of that. We know that there’s going to be some bumpy roads or rough waters, however you want to categorize it. We just want to limit that to one or two runs instead of five or six runs."

Weaver seemed to be turning over a new leaf a few starts ago, when he no-hit the Reds for 6 1/3 innings on April 11. He was aggressive with his fastball, used his changeup effectively and pitched with an edge.

In his four starts since, though, he has not lasted more than five innings and has allowed 17 runs in 17 innings.

"It’s unbearable," Weaver said. "It’s extremely frustrating because you know -- you obviously want to have success, but you at least want to give your team a chance to win a ballgame. Tonight, it’s just, I mean, it’s just a devastating blow. How are you supposed to come back from six runs after two innings? It’s beyond frustrating."

What the specific problem is remains a mystery. Weaver maintains that he is close to figuring it out and pointed to the final two innings of his outing Wednesday as an example.

"That's kind of what I'm fighting right now," Weaver said. "It’s like I’m expecting the pitch to do what it’s supposed to do, and it’s coming off a tick one way or the other and it’s not creating the consistency that we saw the last two innings. Those innings, for whatever reason, it clicked and synced. That’s what I’m trying to achieve. That’s the mindset every time.

"The first two innings, I can’t explain it. It’s something I’ll continue to push and work on with these days in between and get it right for the next time. It’s just a teeny, little, minor adjustment from going out and putting up at least six innings with minimal runs and having a chance to win the game."

To hang onto his spot in the D-backs’ rotation, Weaver is going to have to figure it out sooner rather than later.

Right now, the D-backs are down two starters with Taylor Widener and Merrill Kelly on the injured list. Kelly is expected to be able to make his next start -- perhaps as soon as Saturday -- but Lovullo did not want to say whether Weaver was running out of time.

"I don’t want to go that far with any of this right now," Lovullo said. "It’s a tough game. He’s got to digest the game. We’ve got to digest the game. I don’t want to go there. We’ve got one thing to do here and that’s teach. He’s got one thing to do and that’s accept that teaching and continue to give us input so we can keep getting better day by day. That’s as far as I want to go with that."