Pablo Sandoval, battling head congestion, wasn’t at his most energetic while gutting through the Giants’ annual FanFest on Saturday. But that didn’t prevent him from jabbing with a few of his teammates, who will be his foes in the World Baseball Classic next month. He jokingly vowed to turn and burn on Team USA pitchers Jeremy Affeldt and Ryan Vogelsong, and Team Mexico reliever Sergio Romo, too. And why not? Sandoval was the World Series MVP. He was named MVP of the Venezuelan Winter Legue championship series, after leading Magallanes to its first title since 2002. How about WBC MVP as well? “Watch out!” said Sandoval, wearing a deep red Venezuela cap and jersey. “Uh, no,” said Affeldt, as he shared a Q&A stage with the Panda. “I’ll just throw a rosin bag and you’ll swing at it.” As everyone knows, Sandoval is a free swinger. He’s able to barrel up pitches from his eyes to his shoe tops. But nobody’s got a better scouting report on him than his own Giants teammates.