PHOENIX -- There will be little rest for Caleb Smith tonight after the D-backs left-hander struggled on the Chase Field mound Sunday afternoon.

Smith gave up five runs and was not able to get out of the second inning as the D-backs fell to the Dodgers, 13-0.

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"It’s real hard," Smith said about how he processes a loss like this. "That’s all I think about. Especially after a bad outing. I’m going to go home and I’m not going to be able to sleep tonight."

It's not the first time Smith has struggled against the Dodgers. Back on July 10 at Dodger Stadium, he allowed nine runs without retiring a batter in the second inning.

This time around, it wasn't so much that the Dodgers hit him hard, but rather that he hurt himself with walks. He walked two in the first inning and another three in the second.

"They’re a good-hitting team, but they didn’t beat me," Smith said. "I just beat myself. I’ve been doing that for three of the past four outings I’ve had. Walks have killed me. I’ve just got to stop walking people."

In those three starts that Smith referred to, he has allowed 19 runs and walked 11 in just 8 2/3 innings.

Knowing the problem -- too many walks -- is one thing, but fixing it is another when you're not sure what the cause is. Smith was asked if there was something off in his mechanics.

"No, I don’t think so," he said. "My [between-start] bullpens, they’re good. There’s no control issues there. I don’t know if it’s just I get in the game and I’m trying too hard or what. I’ve got to figure it out. I’m going to."

While saying he might be trying too hard, Smith also said it could be a "lack of focus." But whatever the reason, the D-backs need him to figure it out.

"Commanding the baseball is something that he's done very well in the starts that he's performed well," D-backs manager Torey Lovullo said. "So we have got to get him back to that spot when he gets out there and he's dominant and throwing strikes and mixing up his pitches."

Smith was close to getting out of that second-inning jam without any damage, which is why Lovullo stuck with him for what, in hindsight, was one too many batters.

The Dodgers loaded the bases with no outs and Smith then went 3-0 on pitcher Julio Urías, which prompted Lovullo to get Matt Peacock up and warming up in a hurry in the bullpen.

"You want to give your starting pitcher a chance to work through some of those early wobbly moments," Lovullo said. "But then it became apparent to me and also in my discussions with [pitching coach Matt Herges] that he was really battling himself and he might not recover."

Smith, though, did recover somewhat, getting Urías to pop out and striking out Mookie Betts.

Then the wheels came off.

A walk forced in a run and an infield single scored another. Then veteran Albert Pujols delivered the crushing blow, a three-run double to left that gave the Dodgers a 5-0 lead.

It also ended Smith's day, but it didn't stop him from replaying it over and over in his head.

"It’s hard to forget these," Smith said. "You just have to try. There’s nothing I can do about it now. Thinking about it is not going to help me, but it’s hard not to. I’ve just got to get ready for the next team that I’m facing."

That will come in five days against the Padres in San Diego. Between now and then, the D-backs will try and get him right again.

"We're going to build him up," Lovullo said. "We know that he's hurting. We're going to allow him to absorb what he's feeling and embrace it and understand why it happened. And then tomorrow, get right back after it. We got four days to make some good happen, but we will. That's what we do."