Buster Posey. Andrew McCutchen. Brandon Crawford. Hunter Pence. Evan Longoria. Brandon Belt.

With so many proven major league hitters, the last problem San Francisco manager Bruce Bochy would expect is scoring runs. But, right now, the Giants' offense is a big zero -- as in 0-for-8, or what they were with runners in scoring position during their latest loss.

The Giants' August struggles at the plate continued Saturday with a 7-1 loss to the Cincinnati Reds, and now they send out inconsistent left-hander Andrew Suarez (4-8) to try to salvage the final game of the series Sunday at Great American Ball Park.

The Giants were hoping a stretch of games against non-contending teams such as the Reds, New York Mets and Texas Rangers would generate a late-season surge. Instead, it's starting out as a replay of the last few weeks.

They've won only six of 15 games in August, and they rank next-to-last in the National League in batting average, trailing only the Miami Marlins. They've been held to 53 runs this month, an average of 3.5 per game. And they've hit only two home runs in their last 93 innings and seven in August, the fewest in the majors.

Since June 1, the Giants' starting pitchers' 3.42 ERA ranks in the top three in the major leagues. But an offense that added veterans McCutchen and Longoria during the offseason is proving ineffective.

Overall, the Giants are fourth from the bottom this season with 108 homers -- during one of the greatest home run seasons of all time.

"Some things are hard to explain and this is one of them," Bochy said Saturday. "We'll keep working. We've just been shut down."

The Giants' plate problems are exacerbated away from AT&T Park. They average only 3.5 runs per game on the road, the second-lowest average in the majors. They've scored three runs or fewer in 36 of 64 road games and, not surprisingly, they're 14-49 when they score three or fewer.

All those negative numbers add up to a 61-63 record.

"We keep talking about it and we'll keep working to get this offense firing on all cylinders," Bochy said. "It's going to take somebody to get a hit with men on base to interject some energy and get things going, and that's not happening."

The Giants are in fourth place in the NL West, and they'd have to overtake five teams down the stretch to get into wild-card contention.

Not even Giants ace Madison Bumgarner (4-5) could prevent a third consecutive Giants loss or a ninth loss in 13 games. He'd allowed two runs or fewer in each of his last four starts but was touched up by the Reds for eight hits and five earned runs in six innings.

In contrast, Reds starter Matt Harvey (6-7) looked like the all-star pitcher he once was for the New York Mets, no-hitting the Giants for 5 2/3 innings before being lifted after throwing 6 1/3 shutout innings.

Harvey was supported by Jose Pereza, who went 2-for-4 with a solo homer that made it 1-0 in the fourth inning, and Brandon Dixon, who followed with two-run double on a flair to right field to finish the three-run inning.

"Matt was really good, was really sharp," Reds interim manager Jim Riggleman said. "Jose Pereza had a big hit and that kind of loosened things up. He squared up the ball up really well and that was big for us."

The Reds, who have won the first two games of the series after being swept in three games by the Cleveland Indians, will look for a bounce-back start from right-hander Luis Castillo (6-10).

Castillo made three consecutive impressive starts, giving up three earned runs in 17 2/3 innings, before allowing five runs and five hits in 5 2/3 innings of a 9-2 loss to the Arizona Diamondbacks last Sunday. He'll face the Giants for the first time.

Suarez was strong in his last start, allowing no runs and two hits in six innings of the Giants' 2-1 win over the Los Angeles Dodgers on Tuesday. But that was his first scoreless outing since June 2, and he has a 6.06 ERA in his last six starts. He has a 6.19 ERA in three August starts.

Suarez lost to the Reds 6-3 on May 16, allowing four earned runs and eight hits in six innings.

The Reds had lost 11 of 15 going into the series.