Dunn, who had the day off that day, went to the radio booth to see Uecker, who returned to work this past weekend after undergoing heart surgery on April 30. The meeting took place in the second inning.
Dunn and Uecker have been great friends since Dunn played for the Reds.
"We have addressed that issue. That's about all I'm going to say about it," Riggleman said. "It's unfortunate."
A baseball source said Dunn was not fined for leaving the dugout during the game, but was scolded by Riggleman and general manager Mike Rizzo. Dunn was basically told not to go to the broadcast booth during a game.