MILWAUKEE -- The starting pitchers in Sunday's game between the Milwaukee Brewers are 32 and 31 years old.
One is a veteran with a pair of World Series rings on his hand while the other is a rookie phenom who has bounced around in baseball's wilderness.
The latter is Brewers starter Junior Guerra, who was plucked off the waiver wire a day after the season ended in 2015. Guerra, originally slated to provide some minor league bullpen depth, has emerged as one of the team's most consistent starters, going 6-2 with a 3.06 ERA while striking out 78 in 88 1/3 innings of work.
Milwaukee gave Guerra an extra day of rest coming out of the All-Star break before returning to the mound July 19, when he allowed two runs over six innings but didn't take a decision in Milwaukee's 3-2 loss to the Pirates.
The extra rest came as Milwaukee tries to keep an eye on Guerra's workload. He has pitched one inning more than he worked all of last season while in the White Sox minor league system.
"We wanted to give Guerra a longer break," pitching coach Derek Johnson said prior to his last start. "We think it will help but he wasn't showing any fatigue. He has been very strong.
"It seems like he gets better as the game goes on, which I think is a good trait. ... This is the first time he has been a starter in the big leagues, and the strain and stress of that. You hope it doesn't backfire where a guy has too much time off but I don't think it will happen."
Guerra allowed three runs over seven innings while striking out a career-high 11 in his only career appearance against the Cubs -- a 3-0 Brewers victory May 19 at Miller Park.
Jon Lester (10-4, 2.89 ERA) makes his second start of the second half for the Cubs. He allowed a run over 7 2/3 innings against the Mets last time out but since winning five in a row from May 27-June 18, he's 1-1 with a 5.74 ERA in five starts.
After beating the Mets, Lester said he'd identified some flaws with his delivery that he's since corrected.
"You start worrying about that stuff, you're far gone," Lester said. "Then you're thinking too deep. You're worried about things you shouldn't."
Lester makes his fifth career start against the Brewers. He's 2-2 with a 2.22 ERA in his four previous outings against Milwaukee, but hasn't faced the Brewers this season.
Among Brewers regulars, only Ryan Braun (5-for-13) has more than five at-bats against Lester.
The Brewers looks to take their second consecutive series with the Cubs, who have still won 18 of the last 26 meetings between the National League Central rivals.