"Giving our players one more opportunity to earn a spot on merit, I believe, is the right thing to do," Watson said.
Watson will take the top nine players from the Ryder Cup standings and make his three picks ahead of the 40th Ryder Cup at Gleneagles in Scotland which runs from Sept. 26-28.
"I will use all possible resources in choosing these three captain's choices to complete the best possible team in order to win the Cup back for the United States," Watson added.
The U.S. switched to four captain's picks for the biennial golf match against Europe in 2008.
The points system to determine the 2014 U.S. team begins on April 14, after the 2013 Masters.
Eight-times major winner Watson will lead his players into the match against a Europe team captained by Ireland's Paul McGinley.