As the Giants try to press forward at full speed towards the top of the NL West standings in hopes of defending their World Series title, they've found themselves in quite a predicament: Their locomotion is running direly low on coal.

With pitcher Tim Lincecum and catchers Hector Sanchez and Andrew Susac already out for the season, star right fielder Hunter Pence sidelined with an oblique injury, left fielder Nori Aoki dealing with concussion symptoms, and shortstop Brandon Crawford day-to-day with calf and oblique injuries, another pair of Giants caught the injury bug on Wednesday.

After diving for a groundball in the sixth inning of the Giants' 2-1 loss to the Arizona Diamondbacks on Wednesday, second baseman Joe Panik, who had been sidelined for a month with lower back inflammation, later left the game with discomfort in his lower back.

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"It just didn't feel right," Panik said after the game. "I don't know how far back [in the rehab process] we're going to go. I definitely didn't feel well. Something was aggravated. It just kind of came back a little."

As misfortune continues to batter San Francisco in the latter stages of the season, Panik's injury was preceded by catcher Buster Posey being struck from the lineup with pain in the left ankle he had surgery on in 2011 after shattering it in a gruesome home-plate collision.

While Posey's absence from the lineup appeared to be more of a preemptive resting, Panik's injury could keep him away from the field for an extended period of time once again.

Nonetheless, the 24-year-old second baseman is determined to get back into action for the Giants before the season ends.

"I'm a competitor," Panik said. "It all depends on how I'm feeling. If I'm able to, I want to get out there, but at the same time you have to be smart."

With the Dodgers leading the NL West by 8 ½ games with just under two dozen games remaining in the season, the Giants will need all hands on deck to catch their division rivals.

As for the barrage of injuries that has hit San Francisco, manager Bruce Bochy is flabbergasted.

"It's just non-stop right now," Bochy said. "It's just really unbelievable."

CSN Bay Area