Wetteland, who replaced Bobby Natal before this season, was not available for comment. He was seen waving goodbye to reporters as he rode his motorcycle out of RFK Stadium.
"It was a difference of opinions to the point where he didn't perform the way I wanted things done in the bullpen," Robinson said. "I talked to him on a number of occasions. I've never talked to a bullpen coach as much as I've talked to him about that situation and the problem that started in Spring Training and carried over until [Wednesday night]. I had enough to a point where he said, 'I hear you, but I'm going to do things my way out there.'
"Over a period of time, we were not getting the best out of the guys out there that I've seen in the past. There have been spots of good outings, but it hasn't been a consistent type of thing. They seemed focused more on practical jokes and fooling around in the bullpen rather than concentrating on the game. I couldn't put up with it anymore."
Robinson declined to go any further about the problems with Wetteland, but according to a source close to the situation, Robinson was upset after being told by an informant that Wetteland would often undermine the skipper when it came to handling a pitching staff. Wetteland, according to the source, denied to Robinson that he made any such comments.
Robinson, according to the source, felt Wetteland changed the personalities of the relievers -- especially Chad Cordero and Gary Majewski. They would often follow Wetteland's advice rather than that of pitching coach Randy St. Claire.
The relievers also were also known to shoot firecrackers in the bullpen and the locker room.
When reached by phone, Cordero declined to comment, and Majewski was not available for comment.
"It's an unfortunate situation that Frank decided that he needed to make a move," reliever Mike Stanton said. "John will be missed. He helped a lot of the young kids. There were some differences that could not be dealt with anymore."
Wetteland -- whose 330 career saves currently rank ninth on baseball's all-time list -- was appointed Nationals bullpen coach on Jan. 27, 2006. He has been offered another position within the organization.
The Nationals will hire a bullpen coach on Friday for the rest of the season. Spin Williams, the team's pitching coordinator is a possible candidate.
Asked whether he had concerns about how the bullpen would react to the move, Robinson said, "I don't care. Maybe they will get mad and get someone out."