LOS ANGELES -- On their first day in the City of Angels, the Giants found out they will be without center fielder Angel Pagan for the majority of the regular season.

The team announced Monday that Pagan will have surgery Tuesday to repair a torn tendon in his left hamstring. Pagan is expected to miss 10 to 12 weeks, a prognosis that could put him out of the lineup until the final two weeks of the regular season.

"It's a loss, there's no getting around it," manager Bruce Bochy said. "You lose your leadoff hitter and the guy that led off for you all the way through the World Series last year."

Through 76 games this year, the Giants hardly resemble that team that paraded down Market Street on Halloween. A 3-1 loss to the Los Angeles Dodgers dropped the Giants to 38-38. This is the first time since 2008 that they do not have a winning record at this point of the season.

The Giants will have to turn the tide without Pagan, their sparkplug at the top of the lineup. Pagan had not played since May 25 and received a cortisone injection and platelet-rich plasma injection in a bid to return to the field. He neared a return last week and went on a rehab assignment with the San Jose Giants, but while running out a ground ball, Pagan felt a pop behind his knee and crumpled to the ground before being carted off.

When an MRI revealed a tear, Pagan said he would do what was necessary to get back to 100 percent.

"I depend on my legs," he said. "If I was a first baseman, maybe I could go through and play at 70 percent. Playing 70 percent for me is not going to do it."

The Giants now will play the majority of their season without a player who was such a key cog last year that he was given a four-year, $40 million deal in December. Bochy said he would lean on the current rotation of outfielders to make up for Pagan's absence. Gregor Blanco will get the majority of the time in the leadoff spot.

"We'll keep going like we've been going," Bochy said before the game. "I like the way Gregor has been playing. He's done a great job. We'll try to match it up with (Andres) Torres and (Juan) Perez, too. We have to get other guys to step up and soften the blow when we lose these regulars."

In that department, the Giants had mixed results Monday. Pablo Sandoval returned to the lineup for the series opener against the Dodgers, but Joaquin Arias strained his left hamstring in the second inning and will miss at least a couple of days. The Giants made two additions to an ever-evolving roster, bringing back reliever George Kontos to replace struggling reliever Jean Machi and recalling left-hander Mike Kickham to fill in for starting pitcher Chad Gaudin, who was put on the disabled list with an elbow contusion.

The flurry of moves did little to jolt the Giants from their slumber. Monday's loss brought forth a set of familiar themes and one new, frightening one. In their first matchup with Dodgers rookie phenom Yasiel Puig, the Giants joined the growing list of teams that could not stop the powerful outfielder.

Puig opened the scoring in the first inning with a solo homer to right on an outside changeup that was exactly where Madison Bumgarner wanted it.

"That didn't make much sense to me," Bumgarner said. "I felt it was right there on the edge of the plate. You don't see many guys do that."

Catcher Buster Posey compared Puig, who has seven homers in 20 games, to last year's breakout stars, Mike Trout and Bryce Harper.

"When he's getting something to hit, I don't think he's missing it," Posey said.

The Giants missed plenty of opportunities against Hyun-Jin Ryu, scoring just one run off the rookie despite amassing eight hits and four walks.

Bumgarner kept the Giants in the game. He cruised through the seventh and was sent back out for the eighth with his pitch count at 107. Nick Punto led off with a pinch-hit double, and Bumgarner was pulled after making a throwing error on Mark Ellis' sacrifice bunt.

Puig welcomed Kontos back to the big leagues with a single to left, scoring Punto. The Dodgers tacked on another run in the inning, and the Giants went down quietly in the ninth.

The Giants dropped to fourth place in the N.L. West and are 3½ games out of first place for the second time this season. Posey said the club just needed to keep grinding.

"You try to draw on past experiences and past successes," he said.

With a growing set of problems on the field and another player headed for surgery off it, that's getting harder and harder to do.

  • Kontos formally appealed his three-game suspension. He was suspended June 12 after MLB ruled that he intentionally threw at Pittsburgh Pirates outfielder Andrew McCutchen the previous night.

    Tuesday's game
    Giants (Mike Kickham 0-1) at L.A. Dodgers (Stephen Fife 1-2), 7:10 p.m. CSNBA