We have our first genuine American shocker. Forget Michael Phelps, who finished out of the money in Saturday’s 400-meter individual medley swim race; Phelps may have finished a distant fourth, but at least he did qualify for the finals of the race, close call or no. What happened yesterday on the floor of the North Greenwich Arena was something else again: Jordyn Wieber, magazine cover girl and odds-on favorite to be the breakout American Rigby/Retton/Strug star of these Games, failed to qualify for the individual all-around championship, a stunning blow to the U.S. gymnastic team.