MILWAUKEE -- The Milwaukee Brewers have two of the best rookie starting pitchers in the National League -- Zach Davies and Junior Guerra.

Davies, a 23-year-old prospect acquired from the Orioles last summer, fits the mold. Guerra, however, is hardly what one would consider an up-and-comer.

A 31-year-old journeyman who spent four years pitching outside of affiliated baseball, Guerra has not only stabilized the Brewers' starting rotation but he also owns some of the best numbers of any pitcher in the league

Guerra will take the mound on Sunday in the first-half finale against the St. Louis Cardinals at Miller Park.

Called up on May 1 to replace Taylor Jungmann, Guerra has gone 6-1 in 12 starts and after not allowing a run in 15 1/3 innings over his last two starts, his 2.93 ERA would put him 14th in the league if he had enough starts to qualify among league leaders.

He's faced the Cardinals once already this season, allowing four runs -- three earned -- over 6 1/3 innings in a 3-1 loss at Miller Park.

That was the last time that Guerra took a loss. Since then, he's 3-0 with a 2.45 ERA.

"It feels like he's even getting better," Brewers manager Craig Counsell said after Guerra's last outing. "In the biggest spots he seems to step up even a little more."

It's quite an impressive accomplishment for a player who was almost an afterthought when he was claimed on waivers last fall from the White Sox.

"You just have to thank God that he gave you this opportunity of having a good first year," Guerra said. "You just have to keep working hard because nothing is guaranteed."

Guerra will try to prevent another series victory for the Cardinals, who are 12-0-1 in the last 13 with Milwaukee and have taken 26 of 27 since Milwaukee's three-game sweep in June of 2011.

To keep that streak going, St. Louis will turn to veteran right-hander Mike Leake, who is looking to snap a personal four-game losing streak.

Leake allowed five runs over five innings his last time out, but in two meetings with Milwaukee this season has allowed six total runs in 12 innings.

Leake has had plenty of experience with the Brewers, playing all but one half-season of his seven-year career in the NL Central. In 12 career starts against Milwaukee, he's 3-4 with a 4.58 ERA and 3-2 with a 4.81 mark in eight starts at Miller Park.

The Cardinals have battled a slew of injuries over the last week, losing three players to the disabled list in the three days leading up to the Brewers series.

However, St. Louis seemed to have dodged a bullet on Saturday, when tests on right-hander Trevor Rosenthal's left hamstring came back negative, averting yet another disabled list entry.

St. Louis did play without left fielder Matt Holliday, who battled ankle tightness Friday, but Matheny said Holliday was available to pinch-hit, if needed, and could be back in the lineup on Sunday.

"We were a little short," Matheny said Saturday after the Cardinals' 8-1 victory. "But Holliday was available to come and hit late and he could possibly be ready tomorrow. We had good results back from Trevor (Rosenthal). It's going to be day-to-day with no DL, it looks like."

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