LOS ANGELES -- The Giants needed only to look out at the mound Friday night to see how injuries have impacted the National League West race. After filling in for Clayton Kershaw for a month, journeyman left-hander Paul Maholm started in place of the injured Hyun-Jin Ryu for the Los Angeles Dodgers.

Now the Giants will have to weather their own storm.

First baseman Brandon Belt fractured his left thumb when he was hit by a pitch and is expected to miss about six week. The injury to a key slugger put a damper on a 3-1 win over the Dodgers that gave the Giants the best record (23-13) in the National League.

"You've lost your first baseman, and that's a blow for us," Bochy said. "He's a guy that hits in the heart of the order, and there's the job he does (defensively) at first. It's the old bittersweet thing."

Bochy said it was too soon to announce roster moves or a plan for first base, but Belt was already out of the park late Friday night and headed back to San Francisco, where he will see a hand specialist and undergo more tests. The immediate move will likely be the activation of Matt Cain (cut finger), which was going to happen anyway since the right-hander is starting Saturday's game. After that, it gets complicated.

Bochy mentioned Buster Posey, Hector Sanchez, Michael Morse and minor leaguer Adam Duvall as names that had been bandied about in a brief conversation between the manager and management. It's possible that Posey, who occasionally plays first to rest his legs, and Sanchez, a surprisingly stout defender during a spring cameo at the spot, could split the duties.

"These are all things we're going to talk about," Bochy said. "Right now, maybe we'll split it quite a bit."

Whatever option they choose as a bandage, the Giants will be hard pressed to match Belt's production. The 26-year-old is tied for third in the league with nine homers and has started 32 of 36 games at first base. Belt was hurt on the first pitch of the second inning, a sinker that bore in on his hands.

Maholm said he was trying to throw a pitch down and away. "I missed by about two feet," he added.

Belt immediately crouched over in pain and shook his hand several times but stayed in the game after a consultation with trainer Dave Groeschner. After running the bases, Belt was replaced by Joaquin Arias in the bottom half of the inning.

"He couldn't move it," Bochy said of Belt's thumb. "It was just locked. I had a bad feeling that he had to come out of the game and that it was broken."

With one Brandon down, the other two gave the lineup a lift. Brandon Hicks drew a one-out walk in the fifth and Brandon Crawford broke a scoreless tie with a homer to right, his third of the season against left-handed pitchers. The Giants tacked on a third run in the sixth when Hunter Pence walked, took second on a ground out, stole third and scored on an infield single.

The Dodgers got on the board in the bottom of the inning when Yasiel Puig hit a laser shot over the center field wall. Puig, as is his tradition, flipped his bat and then took a slow jog around the bases. Bumgarner approached home plate umpire Will Little as Puig made his way toward third, and when Puig turned for home Bumgarner walked toward him and started yelling.

"I was just congratulating him. That was a really good swing," Bumgarner deadpanned. "I don't know why everybody got so mad."

As players from both teams started walking up dugout steps, Puig held his hands out and yelled a few choice words of his own at Bumgarner. Little and catcher Buster Posey got between the two hulking young stars.

"I think he said thank you," Bumgarner said, when asked what Puig's reply had been. "I'm not sure. I don't speak Spanish well."

For more on the Giants, see Alex Pavlovic's Giants Extra blog at blogs.mercurynews.com/Giants. Follow him on Twitter at twitter.com/AlexPavlovic.

SATURDAY'S GAME

Giants (Matt Cain 0-3) at L.A. Dodgers (Zack Greinke 5-1), 1:10 p.m. CSNBA, FOX Sports 1