Ronaldo may drop out of tournament

The U.S. has a match scheduled on Sunday against the best finisher in the world, yet can't be certain Cristiano Ronaldo will really be Cristiano Ronaldo - or if he'll be on the field at all.For the second time at this World Cup, Ronaldo limped off a Campinas practice field early on Wednesday, long before the scheduled session was done, more gingerly than ever.
 Once again, he had been working out on his own, avoiding any possible contact during drills with teammates. A trainer administered to Ronaldo's left knee for several minutes, first leading him through a series of stretches and then strapping on a heavy ice bag to an area of tendinitis that has troubled the star in recent weeks.