Andrew Luck opens the 2010 season as the most celebrated Stanford quarterback this side of John Elway, a grounded, whip-smart athlete who might emerge as a leading Heisman Trophy candidate as well as a top NFL draft prospect. Luck isn’t looking forward to addressing questions about his NFL prospects all season. He swears he hasn’t thought much beyond this fall even if everyone else in the football universe has speculated about his future. “If he plays as well as we expect him to play, and as well as Stanford needs him to play, then he will be the highest-rated player in the draft next year,” said Trent Dilfer, an ESPN analyst and former 49ers quarterback. Dilfer predicts Luck will travel far because “his lower-body mechanics are as good as anyone I’ve seen playing football right now. I’d put him up there with Philip Rivers, Tom Brady