SAN FRANCISCO -- Rockies leadoff hitter Willy Taveras spent most of Wednesday afternoon getting on base and not scoring. He reached on a hit and two walks but had one run to show for it. But don't expect him to complain about teammates not bringing him home.

Taveras experienced some of the frustration that the heart of the Rockies' order has been dealing with for the entire first month of the season.

With two out in the eighth and Scott Podsednik at second base, Taveras hit a line drive that could have tied the game, but Giants left fielder Fred Lewis made a diving catch and sent the Rockies to a 3-2 loss at AT&T Park.

"I had no idea the ball was going to stay up that long. ... It's just not working," Taveras said.

The Rockies have one of the strongest lineups in the National League, yet they're having repeated difficulties coming up with the big hit. On Wednesday, they left 12 on base and went 1-for-11 with runners in scoring position. It's not like it's new.

The Rockies were 1-for-22 with runners in scoring position while losing two of three to the Giants, who won on Jose Castillo's leadoff home run off Ryan Speier (0-1) in the seventh. It was Castillo's first home run in 450 at-bats.

The Rockies' lack of production in key situations was a persistent problem during a 1-5 road trip. In fact, it's been the case all year. They're hitting .215 (59-for-274) with runners in scoring position for the season.

"Sometimes you go out and it just happens, but we've been putting too much pressure on ourselves," first baseman Todd Helton said. "The pressure's never on the pitcher, even when he's in a jam. The pressure's on the hitter to get the job done. That's all just a mind-set that we have to get over."

The Rockies did all their scoring in the fifth, on Garrett Atkins' sacrifice fly and Ryan Spilborghs' RBI double, but Giants starter Jonathan Sanchez forced a grounder from Jonathan Herrera -- in his Major League debut -- to end the inning with the bases loaded.

Another missed opportunity occurred in the sixth with the score tied, 2-2. Taveras walked and stole second and third with one out. But Sanchez struck out Helton, and Merkin Valdez (1-0) forced Matt Holliday to fly to right.

"I can only speak for myself, and I haven't been doing the job with runners in scoring position lately," Holliday said. "It's frustrating. You want to produce for the team.

"The important hits are with runners on base, and for whatever reason I haven't been able to find the barrel and get the bat head out where I want it."

The loss occurred despite much-improved work from Rockies starter Ubaldo Jimenez. Under threat of losing his spot in the rotation, Jimenez held the Giants to two runs on three hits, with four strikeouts and two walks in 5 1/3 innings. Keeping a close eye on Jimenez, manager Clint Hurdle pulled him after 74 pitches.

One hit off Jimenez was costly -- Aaron Rowand's second homer of the season, to open the second. The second walk, to Lewis to open the bottom of the sixth, set up Randy Winn's RBI single to tie the game. But Jimenez didn't unravel with runners on base the way he had in his previous three starts.

"That's very encouraging," Hurdle said. "He did the things we would have liked to have seen. I would've loved to have seen us have a 5-1 lead and let him work longer in the game for another bit of a test for him. But that wasn't the case.

"The efficiency with the pitches was probably the most significant thing. He had a good, live fastball, he spun some balls, had some good changeups. It was a much better package today."

If the Rockies can extract some consistency out of the rotation, they feel they have the firepower to win games like Wednesday's.

"We're going through a hard time right now, but we'll be there," Taveras said. "It didn't work today, but it's going to work. I'll take my chances with Holliday and Helton anytime."