A.J. Burnett last pitched at Wrigley Field one month ago. It was also the last time he pitched at all.
The right-hander returns from the 15-day disabled list Sunday against the Cubs, but the Pirates haven't missed a beat without their ace, ripping off a nine-game winning streak and vaulting themselves to the top of the National League Central in his absence.
"It's been fun to watch. I've been involved every step of the way, and I can't wait to contribute," Burnett said Friday. "[Returning] any place would be good, but I do enjoy pitching here [at Wrigley Field]."
Burnett has been sidelined since June 14 with a Grade 1 tear in his right calf. His last outing was a 6-2 win against the Cubs on June 8, when he threw 8 1/3 shutout innings before allowing a two-run homer to Alfonso Soriano in the ninth. He'll try to replicate that Sunday in the series finale.
Burnett is 7-2 lifetime against the Cubs, his best winning percentage against any team. He owns a 3.08 ERA, 1.135 WHIP and 3.20 K/BB ratio against them.
Carlos Villanueva, like Burnett, will return to the rotation and start Sunday in place of Scott Feldman, whom the Cubs traded to Baltimore earlier this week.
Villanueva was 1-3 with a 3.93 ERA in eight starts, then moved to the bullpen when Matt Garza came off the disabled list. He has a 2.04 ERA in 16 relief appearances.
Because the right-hander hasn't started since May 14, he'll be limited to 60-70 pitches Sunday, and the rest of the Cubs' bullpen will back him up.
"When he starts, he's going to have to have fastball command," Cubs manager Dale Sveum said. "Coming out of the bullpen, he can get through with his trickery, but when you start, you have to have fastball command and get some outs with your fastball."
Cubs: Soriano beats up Bucs in matinee
• Soriano hit a pair of two-run homers in Saturday's 4-1 Cubs win, giving him 31 in his career against the Pirates, his most against a single team.
He had previously struggled this season against the Bucs, though, posting a .179 average in his first 10 games against the division rivals.
• Current Cubs are hitting a collective .244 against Burnett. Shortstop Starlin Castro has eight singles in 19 at-bats against him.
Pirates: Walker exits game with discomfort in side
• Neil Walker left Saturday's game with discomfort in his right side, which manager Clint Hurdle believes arose during a third-inning strikeout.
The Pirates' switch-hitting second baseman went 0-for-2 before leaving in the fifth, a day after he went 1-for-4 with an RBI triple in a Pirates win.
Walker spent two weeks on the disabled list in early May with a dislocated finger.
• Garrett Jones has two home runs and four RBIs in six career at-bats against Villanueva. Current Pirates are batting .351 with a .977 OPS off the righty.
• The Pirates are 20-11 in their past 31 games at Wrigley Field.
• Center fielder Andrew McCutchen, third baseman Pedro Alvarez, lefty Jeff Locke and closer Jason Grilli were named to the National League All-Star team for the Pirates. Lefty Travis Wood was the Cubs' lone selection. It's the first time since 1981 that the Pirates have had four All-Star selections.
Steven Petrella is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.