Francisco Rodriguez's early season struggles continued Tuesday night when he gave up Mark Kotsay's pinch-hit, two-run homer in the eighth inning that gave the San Diego Padres a 2-0 win against the Milwaukee Brewers.

Kotsay, who played with Milwaukee last year, drove a 1-1 pitch from Rodriguez to right field with one out. Will Venable was aboard on a single.

"It's been a frustrating five weeks of the season," said Rodriguez (0-3, 6.57 ERA). "I'm healthy I have to stop making mistakes. I know what I'm capable of doing and I know I can do a lot better than this."

It was Kotsay's fourth career pinch homer and his first since Aug. 9, 2002, at Cincinnati during his first stint with the Padres. He was signed as a free agent in the offseason for his left-handed bat off the bench and a veteran presence in the clubhouse

Milwaukee's Ryan Braun, who had his first three-homer game and added a triple for six RBIs in Monday night's 8-3 win, went 1 for 4 with a single.

Rodriguez started the eighth and retired pinch-hitter Jesus Guzman before allowing Venable's single and Kotsay's first homer of the season.

"It's command," manager Ron Roenicke said. "I think his stuff is fine. He makes some great pitches. But when he makes mistakes, they're hitting the ball right now. He's a guy we need out there. Every time we bring him in I feel like he's going to do a great job. He's certainly still a great reliever. I think he's going to be fine."

With three pitchers combining on a three-hitter, the Padres got their first shutout of the season.

Andrew Cashner (2-1) pitched the eighth for the win. Huston Street pitched the ninth for his fourth save in four chances.

Starters Edinson Volquez of San Diego and Shaun Marcum of Milwaukee each threw three-hit ball for seven innings. Marcum struck out six and walked four while Volquez struck out four and walked two.

NOTES: Padres LHP Cory Luebke will miss his scheduled start Wednesday after experiencing soreness in his left shoulder during his last start. The Padres plan to call up 37-year-old Jeff Suppan from Triple A to start on Wednesday against the Brewers, one of his former teams. The Padres say Luebke will miss at least one start and isn't a candidate for the disabled list. ... Suppan spent the entire 2011 season with Triple-A Omaha in the Royals' organization. In 2010, he was a combined 3-8 with a 5.06 ERA with Milwaukee and St. Louis. ... The Brewers are scheduled to counter with Yovani Gallardo (1-2, 6.08). ... Brewers 1B Mat Gamel left after twisting his right knee when he hit the low wall going after a foul ball. He was hurt trying to catch a foul by Nick Hundley with two outs in the first inning. He stayed in the game for the final out of the inning but was replaced by pinch-hitter Travis Ishikawa in the second. Ishikawa also replaced him at first. ... In the top of the first, Padres 1B Yonder Alonso tumbled over the wall going after a foul ball. He stayed in the game. ... Padres LF Carlos Quentin was 2 for 3 with a three-run homer while serving as the designated hitter in his first rehab start for Triple-A Tucson. He began the season on the disabled list after undergoing knee surgery during spring training.