The other four starters, to borrow a Spring Training phrase, are still working on things.
Right-hander Mike Fiers was the last man out of the gate Saturday at Miller Park, and he was hit hard in a 9-2 loss to the D-backs that sealed Milwaukee's second straight losing series. The Brewers will turn back to Opening Day starter Yovani Gallardo on Sunday.
"Obviously we've made some mistakes pitching, but I really believe that our starters -- really, our pitchers in general -- are better than what they've shown," catcher Jonathan Lucroy said. "I know it because I've seen it."
What Lucroy has seen so far is one quality start, from Lohse, who allowed one run in six innings of Friday's series-opening 3-1 loss to the D-backs.
The Brewers' other four starting pitchers -- Gallardo, Marco Estrada, Wily Peralta and Fiers -- have combined to allow 17 earned runs and 34 hits in 20 1/3 innings.
"Our starters besides Lohse have struggled," manager Ron Roenicke said. "And Michael, even though we think he's a guy that's going to pitch well, we need to get him on the right track so this doesn't continue to go on. We're scuffling with our bullpen already, and we have off-days and eight guys down there."
Fiers was knocked around the same way he was in Spring Training, and the same way he was last September as he pushed past his workload in previous seasons. Against Arizona, he surrendered six earned runs in five innings on nine hits, including a pair of two-run home runs.
Even the outs were loud; four of the D-backs first five outs were well-struck fly balls that pushed Brewers outfielders back to the warning track.
D-backs right fielder Jason Kubel hit one beyond the warning track in the fourth inning, a two-run home run that gave Arizona a 3-2 lead and highlighted a three-run outburst. Paul Goldschmidt, who'd doubled ahead of the Kubel homer, hit a two-run shot of his own the following inning to make it 6-2.
"I thought I threw the ball pretty well. They capitalized on a couple of mistakes, and that was the game," Fiers said. "Two key at-bats in the game."
Afterward, Roenicke was asked the same question he was asked last September: What explains Fiers' drop-off?
"Well, commanding the baseball is the main problem," Roenicke said. "That can be because of lack of confidence. It can be fatigue. It can be getting out of rhythm with our delivery. It can be all those things. So, we need to find out what the answer is and get him on the right track. We need this guy to pitch well for us.
"We'll look. Rick [Kranitz, the pitching coach] is always looking at the film, and he'll check out the delivery and see if there's something that he can see that could cause him to miss so much with all of his pitches."
This was not the start to the season that Fiers envisioned.
"It's not a great feeling when you give up six runs in five innings, but I can't do nothing about this game right now," Fiers said. "I have to look forward to my next start and get ready for St. Louis. Just because I started the year off bad doesn't mean I can't come back and pitch well next outing. I'm not looking at this start as the whole year. It's one start."
There were already questions on Saturday about his next start. If the Brewers keep their five starters in line, he would pitch Friday in St. Louis. But an off-day on Thursday allows for flexibility; the Brewers could theoretically skip Fiers and bring back Gallardo on regular rest.
They could also move left-hander Chris Narveson from the bullpen to the rotation. Or, try someone from a Triple-A Nashville rotation that includes prospects Tyler Thornburg, Hiram Burgos and Johnny Hellweg.
"But we also want to make sure we're giving guys a good enough chance to get in a groove and hopefully be the guy we saw last year," Roenicke said.
Pitching was not the Brewers' only problem on Saturday. They committed three errors, including two in the seventh inning that spotted the D-backs two unearned insurance runs. And without injured stars Ryan Braun and Aramis Ramirez in the middle of the lineup, Brewers hitters were 1-for-7 with runners in scoring position.
With Braun sidelined by a stiff neck Saturday and Ramirez placed on the disabled list with a sprained left knee, the Brewers mustered only two runs in six innings against D-backs left-hander Patrick Corbin, who walked one batter and struck out two.
Second-year Brewers shortstop Jean Segura did much of the damage, matching his career high with three hits, including an RBI double in the second inning that gave the Brewers a 2-1 lead.
Corbin was particularly effective after that. He retired the next eight batters without a ball hit past the infielders.
"Corbin putting up a couple of zeros and keeping it at a one-run ballgame was huge, because as an offense, you're one swing away you don't feel like, 'Oh gosh, we need to get going,'" Goldschmidt said. "There's no pressure, so that was a great job by him after giving up a couple of early runs."
The Brewers hope to have Braun back in the lineup on Sunday, when they will try to avoid being swept.
"I really believe that we're going to step up and start beating some people pretty good," Lucroy said.