A rain delay of almost three hours turned what was already scheduled to be a long day of golf Saturday into an even longer one.
Only two of the six foursomes matches could be completed before dark, meaning eight players from each of the 12-man teams will have to return to the Muirfield Village Golf Club at sunup to complete Friday's play.
There will then be 10 more team matches played Saturday, five in the fourball format during the morning and five foursomes in the afternoon.
Saturday's action will begin with the Americans holding a 4 1/2 to 3 1/2 lead over the International Team, made up of the best players in the world from outside the United States and Europe.
The United States will have the lead in two of the four unfinished matches when the action commences on Saturday and the International Team will be out front in the other two.
Mickelson and Bradley needed just 30 strokes to play the front nine Saturday and went on to defeat Jason Day and Graham DeLaet 4-and-3. The Americans trailed by a hole when Mickelson started the American run by holing an 18-foot eagle putt at the par-5 fifth.
Three of the remaining matches were not close when play came to an end. Americans Steve Stricker and Jordan Spieth had a 3-up lead over Branden Grace and Richard Sterne with four holes remaining while Tiger Woods and Matt Kuchar were 3-up with six to play against Louis Oosthuizen and Charl Schwartzel.
The lone close match remaining, and one that could be pivotal in the final standings, saw Angel Cabrera and Marc Leishman take a 1-up lead with five to go in their match with Webb Simpson and Brandt Snedeker.
Forecasts call for a 40 percent chance of thunderstorms both Saturday and Sunday.