By now it seems pretty clear that Bruce Arena is playing it very mysterioso to confuse the Czechs, Italians and Ghanians — a closed-door match yesterday in which his players don't wear numbers; no comment from any American on that match, even on the official United States Web site; and a shroud of silence so complete that a panic swept through the Big Soccer bulletin board yesterday and today among United States fans afraid that Kasey Keller had been hurt and that the team was hiding the injury. Keller doesn't seem to have been injured, but the fact that there was confusion is probably fine with Arena.The close-to-the-vest approach may take a toll on Arena's players; yesterday, DaMarcus Beasley called it "irritating." But the real aim of Arena's secrecy would appear to be the opposition, and it seems to be hitting its target. At least that's the impression left by the Italian coach, Marcello Lippi, who told Jere Longman in The New York Times Play magazine Sunday that Italy's "concentration is urgent when playing against the Americans because of their 'high technical level,' 'good athletic qualities' and 'discreet organization.'"