SAN FRANCISCO — Madison Bumgarner has spent the first part of this postseason watching his teammates pick him up after disappointing starts in the first two rounds. Now he'd like to pay them back. Though both Pablo Sandoval and Barry Zito turned in surprise performances in Wednesday's Game 1 win, Bumgarner remains the real wild card of this World Series between the Giants and Detroit Tigers. If the 23-year-old left-hander can manage a victory in Thursday night's Game 2 at AT&T Park, he'll put the Giants in a commanding position as the series shifts to Detroit. Of the 36 teams that have taken a 2-0 lead in the World Series after two home games, 29 went on to win the World Series. Overall, that number holds a similar rate of 40 of 50 teams. But taking that two-game lead is easier said than done because Bumgarner's struggles and loss of velocity have been one of the few lowlights for San Francisco this postseason. They even created some speculation that he wouldn't even make the Giants' rotation in the World Series. He gave up four runs in 4 1/3 innings of work against the Cincinnati Reds in a 9-0 loss in NLDS Game 2 and then gave up six runs (including two homers) in 3 2/3...