Ekpo, 20, spent much of the spring in Crew's preseason training camp but returned to Nigeria in March to take part in Olympic Qualifying. Nigeria defeated South Africa, 3-0, on March 26, to advance to the 2008 Olympic finals.
"We are very excited to have Emmanuel join our team," said Crew coach Sigi Schmid. "He played well with us in Florida, and he presents a number of options for us. He has the ability to play in the attacking part of midfield, centrally, and out wide, as well. He is a player with international experience and a very bright future ahead of him."