HOUSTON -- Insufficient hitting, sloppy defense and limp relief pitching combined to doom the Giants to a 12-4 loss Tuesday night to the Houston Astros.

The Astros, winners of six consecutive games, erased a 3-2 Giants lead with an eight-run seventh inning that featured Lance Berkman's fourth career regular-season grand slam. No less than four relievers were charged with runs in that inning.

Yet manager Bruce Bochy seemed mostly upset with San Francisco's offense, or lack of it. The Giants went 1-for-9 with runners in scoring position and twice loaded the bases with one out or fewer and came away with just a single run each time.

"It would be nice to have a big inning and put a crooked number up there," Bochy said.

Fortunately for the Giants, right-hander Tim Lincecum avoided a significant injury when he emerged with just a bone bruise after being struck on the side of the right knee by Brad Ausmus' fifth-inning line drive. X-rays revealed no fracture, but Lincecum's status for his next scheduled start Sunday at Atlanta remains uncertain.

"That's the only good news we got tonight," Bochy said, referring to Lincecum's condition.

Although the Giants crumbled after Lincecum's departure, center fielder Aaron Rowand denied that they were shaken up by the sight of their 24-year-old All-Star limping off the field.

"We were all obviously worried about Timmy and hoping that there wasn't any fracture or anything broken, but I don't think that affected the way we went about finishing up the game," Rowand said.

The Giants' evening began souring before Lincecum departed. Houston scored a pair of third-inning runs off him on a Darin Erstad double that left fielder Fred Lewis struggled to corral and a fielding error by second baseman Emmanuel Burriss, who was surprised by the odd spin on Miguel Tejada's one-hop grounder.

"We couldn't make a play all night," Bochy said.

That lapse was mild compared to Houston's seventh.

Trouble started after Ausmus drew a one-out walk from Alex Hinshaw. Facing Tyler Walker (4-7), pinch-hitter Hunter Pence singled and Mark Loretta walked to fill the bases.

"The walks are killing us," Bochy said. "It seems like every time there's a big inning, there's a walk involved."

Jack Taschner replaced Walker and yielded Erstad's two-run single to short left field. After Tejada singled to reload the bases, Berkman belted a 3-1 pitch over the Crawford Boxes in left. Taschner yielded Geoff Blum's double before Ty Wigginton homered off Geno Espineli.

Watching Taschner work from the outfield, Rowand sensed that the left-hander was thriving. Erstad and Tejada hit tough-looking pitches, and Taschner wasn't giving in to Berkman.

"I thought he pitched Berkman well. He was just up, just down, just out," Rowand said. "He was picking at the [strike] zone, trying to get him to get himself out, chase a pitch a little out of the zone."

But once Taschner fell behind on the count to Berkman, he had to throw a legitimate strike. Taschner opted for a fastball, the pitch he feels most comfortable using against a right-handed batter. The result wasn't a complete shock.

"The guy's a .300-plus hitter every year for a reason," Taschner said of Berkman. "You put him in a hitter's count and he's not going to make a mistake."

The Giants' all-around subpar performance might have been disheartening, but it shouldn't have been demoralizing, in Rowand's view.

"When you get waffle-stomped like that, it's still not as bad as the one-run games you lose, because those are the ones that everybody goes home and reflects about what they could have done to change the outcome," he said.