Dibble, a member of the "Nasty Boys" relief corps of the early 1990s, joins Nationals broadcasts after stints with ESPN and Fox Sports.
"This is part of a dream, to be a major league broadcaster," he said. "I've wanted to do this since I retired."
Dibble's hiring comes after Sutton, a Hall of Fame pitcher, was released from his contract to return to the Atlanta Braves as an analyst on their radio broadcasts. He had worked with the Braves for 17 years before joining the Nationals in 2007.
Most recently, Dibble has co-hosted a show on Sirius XM Radio and worked on Fox Sports as a baseball analyst and a co-host on the "Best Damn Sports Show Period." He previously worked for ESPN as a baseball analyst on radio and television, occasionally pairing with MASN play-by-play announcer Bob Carpenter. Dibble said he will continue to appear on Sirius XM five days a week during the season.
"I'm excited about Rob coming to D.C.," Carpenter said. "I actually worked a handful of games with him years ago at ESPN. He treated me great. We became friends. I have a lot of respect for him as a player and as a broadcaster. I think fans will like him. He's got a little bit of an edge to him."
Known for his hard fastball, Dibble pitched for six seasons in the majors between 1989 and 1995, compiling 89 saves primarily with the Reds. He and fellow reliever Randy Myers shared the 1990 National League Championship Series MVP. He didn't allow a run in the Reds' World Series sweep of the Oakland Athletics.
As a player and commentator, Dibble became well-known for his fiery personality. He got into a well-publicized scuffle with Reds manager Lou Piniella in 1992, and while with ESPN in 2002 he drew the ire of Mets manager Bobby Valentine after questioning the toughness of one of the team's pitchers.
"I'm not going to say I was a model citizen, but I'm not going to lack the etiquette the game demands," Dibble said.
He is the fourth analyst for the Nationals since the team arrived in the District in 2005, following Sutton, Tom Paciorek and Ron Darling.
"We are thrilled to have a talent like Rob Dibble join our broadcast crew," Nationals president Stan Kasten said in a statement. "His enthusiasm and knowledge will quickly make him very popular among Nationals viewers. Rob and I talked today about the three things we know he will be: honest, informative and fun."