Spieth, McIlroy slam Dustin Johnson non-decision
American Johnson was told he could face a penalty for causing a ball to move on the fifth hole of his final round on Sunday.
The 31-year-old is bidding to win his first major and there remains uncertainty over his position on the leaderboard, due to the potential penalty.
World number two Spieth and the third-ranked McIlroy were left bemused by the decision not to make a ruling on Johnson.
McIlroy tweeted: "This is ridiculous… No penalty whatsoever for DJ. Let the guy play without this crap in his head. Amateur hour from @USGA."
The Northern Irishman followed up: "This isn't right for anyone on that golf course. If it was me I wouldn't hit another shot until this farce was rectified."
Spieth was similarly upset and wrote on Twitter: "Lemme get this straight.. DJ doesn't address it. It's ruled that he didn't cause it to move. Now you tell him he may have? Now? This is a joke?"
Johnson has struggled to close at majors previously, with 11 top-10 finishes to his name without a victory.