Aubrey Huff’s walk brought home the decisive run in the seventh inning for the Giants. (Luis Alvarez/ASSOCIATED PRESS)

Life without Ryan Zimmerman continued for the Washington Nationals with the new, demoralizing knowledge that their best player will not return for another six weeks. “We’re going to have to find ways to win games without him,” General Manager Mike Rizzo said.

Saturday afternoon, when the opposing starter all but handed them a victory, the Nationals found a historic way to lose.

Hours after they learned Zimmerman will need surgery to repair a torn abdominal muscle, the Nationals proved how much they miss him in a 2-1 loss to the San Francisco Giants at Nationals Park. Giants pitchers allowed nine walks and hit three batters, but the Nationals became the first team in the live-ball era to score less than two runs when presented that concoction of wildness.

Giants starter Jonathan Sanchez walked or hit seven of the first 10 batters he faced, but the Nationals left the bases loaded twice in the first two innings, the three most crucial outs made by the middle of their lineup. The missed chances gave John Lannan a minuscule margin for error, and he capped 62 / 3 strong innings by walking pinch-hitter Aubrey Huff — after Manager Jim Riggleman had ordered the intentional walk of a backup catcher — to force home the decisive run.

The Nationals waited until the final, bitter pitch to waste their last chance. With two outs, a full count, the bases loaded and most of the 28,766 chanting, “Let’s go, Nats,” cleanup hitter Adam LaRoche swung through closer Brian Wilson’s change-up. All three runners trudged off the field, LaRoche along with them, having left them loaded for the second time.

The Nationals are hitting .222 with runners in scoring position this season, a problem compounded by Zimmerman’s absence in the heart of the order. When crucial situations arise, the dearth of clutch hits has made its way into hitters’ heads.

“I think it has a few times with us,” LaRoche said. “I don’t think there’s any question. When you’re not scoring runs and leaving guys out there, it starts to wear on you as a team. It makes each one of those opportunities seem more important than it is. Right now, we’re just kind of standing still.”

Once the Nationals let Sanchez escape, they produced two hits all game. Only six of their final 31 hitters reached base, which included a stretch of 21 outs in 24 plate appearances.

The offensive shutdown finally caught up to Lannan in the seventh inning. Miguel Tejada began the rally with an infield single to first base, and with two outs Mike Fontenot laced a ground-rule double to center field, putting runners on second and third and giving Riggleman a tough decision.

On deck stood Eli Whiteside, the usual backup catcher who had tied the game in the third with a solo homer. Riggleman could have brought in Tyler Clippard, the man he has trusted all year to stifle rallies. He could let Lannan face him. Or he could have walked the career .232 hitter and forced the Giants to use a pinch hitter in the pitcher’s spot; on deck stood Huff, a left-handed batter who last year hit .296 against lefties.

First, Riggleman decided to stay with Lannan, whom he wanted to give the chance to earn a win. “Every now and then,” Riggleman said, “you make a decision for your starting pitcher.”

Riggleman chose to intentionally walk Whiteside, which loaded the bases with two outs. Riggleman wanted the lefty-on-lefty matchup. Huff, the soul of his team, walked to the plate for an at-bat that could decide the game.

“Huff’s a great hitter,” Riggleman said. “But there’s a reason he didn’t start that game: Lannan was pitching.”

Lannan started Huff with three curveballs, and evened the count at 2-2 with a change-up Huff fouled away. Lannan tried a fastball on the corner, close, but “it was a ball,” catcher Wilson Ramos said.

Huff dug in. Ramos called for a change-up. Lannan trusted the pitch but did not quite follow through enough, which kept the pitch up: Ball four.

“The right decision to make was to just bring Clippard in,” Riggleman said. “I should have done that. That’s one that’s on me.”

Lannan had pitched well — two runs on six hits and two unintentional walks — but the final, deciding batter he faced left him shaking his head, muttering as he walked into the dugout.

“I blew it with Huff,” Lannan said. “I pitched too well to let the game be decided on that walk. I just didn’t get that pitch. It’s the one that’s going to haunt me.”

The outcome, really, should not have come down to Riggleman’s decision and Lannan’s walk. It should have been decided innings earlier, when Sanchez imploded. He allowed eight of the first 11 batters he faced to reach base — five walks, two hit batters, one RBI single by Rick Ankiel and, for good measure, a wild pitch. The Nationals somehow managed one run out of that mess.

In the first, Michael Morse watched four batters walk, then swung at the first pitch he saw and grounded out. In the second, Werth struck out looking and LaRoche grounded to first ending a bases-loaded, one-out rally.

One month into 2011, the Nationals have pitched well enough to contend, but their hitting has stuck them six games back of first place. They were not happy — “there’s a lot of irritated people in that clubhouse,” Riggleman said — but they were still hopeful.

“We’ll get it going here,” Werth said. “We’ve got a long way to go.”