Yovani Gallardo and Jake Arrieta had been rolling along until their most recent outings, but neither is fretting over one bad day in an otherwise solid campaign for each starter.
Gallardo takes the mound for the first-place Milwaukee Brewers as they face Arrieta and the Chicago Cubs on Monday night at Wrigley Field.
After holding opponents scoreless over his previous 16 2-3 innings, Gallardo (6-6, 3.54 ERA) allowed three runs in the first inning Wednesday and gave up four with four walks in four innings of a 7-4 loss to San Francisco.
"Lately he's been pretty good," manager Ron Roenicke said. "It's just one of those days. I don't know what happened."
The right-hander had walked four over his previous five starts combined.
"The past few starts, I think, everything was right in place," Gallardo said. "But you know what? That's how this game is. Sometimes there are certain things you can't explain."
Gallardo has let his pitching do the talking against the Cubs over the last few years, though, and he's been especially solid at Wrigley. He's 5-2 with a 2.70 ERA in his last nine overall starts against Chicago, including 4-0 with a 1.86 ERA in his last six at the Friendly Confines - striking out 44 in 38 2-3 innings in that road stretch.
He'll look to better Arrieta (6-3, 2.80), who had mostly shined this season before giving up a career worst-tying nine runs and career-high 13 hits over five innings of a 13-4 loss at Colorado on Wednesday.
The right-hander hadn't allowed more than four runs in his first 16 starts and went 5-1 with a 1.72 ERA in his previous 10.
"I put us in a tough spot there," Arrieta said. "Low pitch count and a chance to get at least another couple innings out of it. I'll build off it."
Arrieta will be making his first start against the Brewers this season after going 1-1 with a 3.00 ERA in 2013. He'll face a Milwaukee club denied a three-game sweep of the Los Angeles Dodgers with a 5-1 loss Sunday that also snapped a three-game winning streak
The Brewers (63-53) were held in check by Clayton Kershaw, who allowed one run over eight innings. Ryan Braun had two hits and drove in the lone run with a single in the first.
After going 4-2 on a homestand against San Francisco and Los Angeles, the Brewers shift their focus to the last-place Cubs (50-66), who avoided a three-game sweep with a 3-2, 12-inning win over Tampa Bay on Sunday.
"There's no teams you can take lightly," manager Ron Roenicke said. "If you face a good pitcher that night and he's on and you don't score, you're going to lose. We realize that if we're not on our game, it doesn't matter who we're playing, we're going to get beat.
"They'll stay focused. That's not to say we won't get in there and get beat, but they know what they need to do."
Chicago had lost three of four before Anthony Rizzo's walkoff hit Sunday. Top prospect Javier Baez went 2 for 6 with an RBI single, but also committed an error at second base that scored a run.
"I think the whole rest of the season is going to be a pretty good test," manager Rick Renteria said. "We're playing some really good clubs, guys who are in the hunt."
Stalin Castro is hitting .405 during a nine-game hitting streak, and he's batting .378 in 37 career at-bats against Gallardo.