The Cubs opened a 10-game road trip with a 4-3 loss at San Francisco after having swept San Diego in three games earlier in the week at Wrigley Field.
Sveum's team fell to 18-33 with the loss in what overall has been a rough season.
"Did I expect to be 15 games under .500?" Sveum asked. "Of course not. You never think that way. I don't care if you're rebuilding or anything. You never think this is going to happen or we're going to be in this position after May.
"You think about each game and winning the ballgame, not that you're rebuilding. That's not my job. My job is to do the best I can with the players I have on an everyday basis."
Although trade rumors have begun to swirl around the Cubs, rumors the Cubs have denied, changes will come eventually, but they might be incremental.
The hottest name in-house is first base prospect Anthony Rizzo, who Friday was named the organization's player of the month for May. Rizzo is tearing it up at Class AAA (Des Moines) Iowa, but he also has been nursing a sore wrist. There has been talk he'd come up and DH in interleague games at American League parks this month, but the Cubs appear in no hurry to rush him.
On top of that, Bryan LaHair is holding down first base pretty well for the Cubs. The Cubs could move LaHair to one of the outfield corners to accommodate Rizzo, but left fielder Alfonso Soriano has hit well for a month, and right fielder David DeJesus quietly has performed well all year.
"But the day Rizzo comes here he's going to play every day," Sveum said. "Whatever we do, who really knows? We keep beating that to a dead horse every day."
--RHP Michael Bowden was designated for assignment as the Cubs claimed RHP Jairo Asencio off waivers from Cleveland. Bowden was little used since coming to the Cubs in the April 21 trade with Boston for OF Marlon Byrd. He was 0-0 with a 7.45 ERA in 10 relief appearances with the Cubs. Asencio will go into the middle of the Chicago bullpen. He had a 5.96 ERA in 18 games with the Indians. "He has a good arm and has put up some really impressive minor league numbers the last couple of years," manager Dale Sveum said of Asencio. "Just another arm. Someone to pick up and see what happens."
--CF Tony Campana was in the starting lineup for the first time since May 21. He replaced RF David DeJesus at the top of the order against Giants LHP Madison Bumgarner. DeJesus is 6-for-34 (.176) against lefties, so manager Dale Sveum felt the time was right to give Campana a shot even though he also hits left-handed. "With DeJesus out of the lineup, that's your viable choice," Sveum said of Campana.
--LF Alfonso Soriano turned a 4-0 deficit to 4-3 in the ninth inning with a three-run homer off Giants reliever Santiago Casilla. It was Soriano's eighth homer of the season. His first seven all came in May. Soriano has an OPS of 1.106 since May 15.
--LHP Paul Maholm took the loss, falling to 4-4 with a 4.82 ERA. He has not won since May 9 and has two losses and two no-decisions in that span. Maholm gave up two runs in each of the first and third innings against the Giants, and he left after 5 1/3 innings.
--SS Starlin Castro was 2-for-4, raising his average to .321. Manager Dale Sveum called rumors late in the week that the Cubs might be interested in trading Castro "absurd." The Cubs have never given any indication they want to trade Castro, and team officials were downplaying any rumors. Castro had one poor play in the field, getting thrown out standing up on an attempted stolen base in the third inning. "It was not a good time for running," he said. "Bad decision."
BY THE NUMBERS: 37 -- Ninth-inning runs scored by the Cubs this year, by far their biggest output in any inning. They scored three Friday night and have outscored their opponents 37-19 in the ninth.
QUOTE TO NOTE: "Some might be warranted, some isn't even close to anything we're ever going to do in this organization." -- Manager Dale Sveum on recent trade speculation involving SS Starlin Castro and other Cubs players
--C Welington Castillo (sprained medial collateral ligament in right knee) went on the 15-day disabled list retroactive to May 19.
--RHP Lendy Castillo (left groin strain) went on the 15-day disabled list retroactive to May 12.
--C Geovany Soto (arthroscopic left knee surgery) went on the 15-day disabled list retroactive to May 17. He underwent a procedure May 18 to repair a torn meniscus. He is expected to be out until mid-June.
--RHP Marcos Mateo (ulnar neuritis in right arm) went on the 60-day disabled list April 4.