With a month to go before the trade deadline, Garza (4-6) lasted only 51/3 innings while giving up two runs on nine hits and three walks. He and fellow starter Ryan Dempster, currently on the disabled list, are the two names most frequently mentioned as trade targets.
Garza and the Cubs enjoyed seeing Rizzo sock his first homer as a Cub — in the fifth inning with Starlin Castro on base.
"Four games so far, he's got two game-winning hits," manager Dale Sveum said.
"It's good to come here and help us win," Rizzo said. "It's a lot of fun when you can do that.
"It's good for us to win and get that monkey off my back by hitting a home run."
Worst-case scenario: It appears third baseman Ian Stewart is out of options for rehabbing his left wrist without surgery.
"Strong likelihood" is the way Hoyer describes it.
"We're probably going to have to make that decision pretty soon," Sveum said, "just (because) there's no progress."
Stewart was acquired from the Rockies in the offseason for Tyler Colvin and DJ LeMahieu but has hit just .201 with five homers and 17 RBIs in 55 games. Those are hardly the numbers Hoyer had in mind when he acquired Stewart to replace Aramis Ramirez at third base.
"It's been frustrating for Ian and frustrating for us," Hoyer said.
Catching on: Sveum, on whether Geovany Soto and Steve Clevenger are in a platoon at catcher:
"Soto is going to catch 60-70 percent of the time. It's not a platoon, but Clevenger is going to get his at-bats. But Soto is still going to catch a little bit more."
Extra innings: Dempster will throw a bullpen session off the mound Monday while continuing rehab from a strained lat muscle. ... Sveum said Chris Volstad will recalled from Iowa for a start Tuesday. He was 0-6 before his demotion in May.