The US team go into Sunday's singles matches at Medinah leading 10-6.
Jose Maria Olazabal, the European team coach said: "Obviously we could not hide anything. We are trailing by four points and we have to put the players that are playing well up there."
Rory McIlroy and Tiger Woods will not face each other for the second Ryder Cup in a row.
The Europe team, who are the current holders of the trophy, would have to match the biggest comeback in Ryder Cup history to win today.