In the top of the third inning, with the count 1-2 and no score in the game, home-plate umpire Joe West said Nationals second baseman Anderson Hernandez struck out swinging. But Hernandez claimed that he fouled off the pitch.
The replay showed that Hernandez's bat touched the ball.
Riggleman came out to argue the call for about a minute with West. Riggleman then went to third-base umpire Paul Nauert to protest the call. As he was talking to Nauert, Riggleman was ejected by West.
"I thought I heard the ball hit the bat," Riggleman said. "When the ball is going through the zone like that -- low and in the dirt -- you can't really see much. I thought I heard the ball and bat make contact. I'm not positive, but I thought it warranted Joe checking with the third-base umpire. He was sure with what he saw and decided there was no need for that."
West, who was working in his 4,000th Major League game as an umpire, was not available for comment.
Bench coach Pat Corrales took over Riggleman's duties, while pitching coach Steve McCatty made the changes on the mound.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.