It was a day of mixed emotions for the Milwaukee Brewers on Tuesday.

They used a pair of late-inning comebacks to sweep a split doubleheader against the Chicago Cubs at Wrigley Field 6-5 and 3-2 but lost starting pitcher Yovani Gallardo in the first game to a left-hamstring injury.

The Brewers used a four-run seventh inning keyed by a three-run opposite-field home run by rookie Khris Davis to beat the Cubs in the afternoon and then got a two-out two-run single in the ninth from Jeff Bianchi to clinch their first doubleheader sweep since Sept. 29 2010.

"Anytime you come back late it's great" manager Ron Roenicke said. "There's a lot of good things in those ballgames. It was a great day — except for Yo. That was really the only negative today."

Gallardo came up lame after throwing a pitch to Darwin Barney with two on and two outs in the fourth inning. He was limping noticeably as he walked around the mound and left the field after a short consultation with Roenicke and trainer Dan Wright.

The Brewers announced afterward that Gallardo was suffering from left-hamstring tightness.

"We're not sure as far as length of time" Roenicke said adding the right-hander would be examined by team physician William Raasch on Wednesday.

It turns out Gallardo first injured the hamstring when he dived to catch a bunt in front of the mound in the third.

"He felt it a little on the dive" Roenicke said. "We went out there he threw a couple warmup pitches seemed to be fine. Came back in they checked him out again and he was fine. Told him if it bothers him don't swing (in his ensuing at-bat) and he swung.

"Then he really didn't feel it until it all of a sudden tightened up on him."

With Gallardo out John Axford was brought in and hit hard from the outset.

He surrendered four consecutive RBI singles before finally striking out Junior Lake to end the inning as the Brewers went from leading 2-0 to trailing 5-2 heading into the sixth.

"It's never an easy situation for anybody to come in from the bullpen like that" said Gallardo who surrendered six hits three runs (earned) and three walks to go along with one strikeout in a 94-pitch outing.

"You're sitting there just watching the game and next thing you know you have to get up and get loose right away. It's a little bit different than somebody calling down and saying you have the next hitter."

Milwaukee pitchers have been plagued by hamstring injuries this season with both Jim Henderson and Marco Estrada spending time on the disabled list after pulling theirs on the mound. Estrada remains on the DL where he's been since June 5.

Wily Peralta missed a start after straining a hamstring earlier in the month in Washington while Kyle Lohse also suffered a hamstring injury running the bases but didn't miss any starts.

"I don't know" Roenicke said when asked what he made of the rash of hamstring pulls. "It's unusual to see hamstring pulls especially with pitchers. I don't remember too many."

Gallardo said that same hamstring also had been bothering him earlier in the month.

"It was actually right before the all-star break in Arizona" he said. "Just went in treated it every day — even during the break — and it was fine. It felt good. Then today for some reason as I dove for that ball it was just a quick move."