"I have never said that Ronaldo is a slave," Blatter told reporters Wednesday on a visit to Vietnam. "But I said slavery with young people, youngsters that European clubs are trying to get 13, 14 and 15 years old boys and bring them to the big clubs. This is in my expression, this is modern slavery." he said "I have never mentioned that for Ronaldo."Oh, well that clears it up so much better.
Football is a business and players are employees. They get paid for their service (even the teenagers). So, by definition it is not slavery.