The Nationals named bench coach John McLaren as their interim manager, but he is not expected to fill the role for the remainder of the season.
Riggleman's announcement caught the Nationals off guard and was even more surprising considering how well the team has been playing. Thursday's victory completed a three-game sweep of the Mariners and was Washington's 11th win in 12 games. It put them over the .500 mark at 38-37.
The 58-year-old was in his 12th season managing a big league team, and has an overall 662-824 record. He's also managed the Padres, Cubs and Mariners. He took over the Nats' job in 2009, taking the reins from Manny Acta, who is now the Indians manager.
Riggleman said that the only thing he wanted to do was talk about his contract, and that he didn't make any demands.
"I want to make one thing very clear -- I wanted a conversation about it," Riggleman said. "I didn't say, 'Pick up my option, or else.' I said, 'I think it's worthy of a conversation when we get to Chicago,' and Mike said, 'Well, we're not going to do that.'"
Rizzo told the players in the locker room after the game, an announcement that caused the celebratory atmosphere to become "somber very quickly," according to Rizzo. Several minutes later, Riggleman talked to the media in the middle of the clubhouse as his former players were preparing to get on a bus to the airport.
A normally low-key, quiet person, it was easy to see that this issue had been bothering Riggleman for a long time.
"You've got to feel there's a commitment to you, and I just didn't feel that way," Riggleman said. "I just felt that it's worthy of a conversation. I just felt that I know I'm not Casey Stengel, but I do feel like I know what I'm doing, and it's not a situation where I felt like I should continue on with such a short leash where every little hill and valley is life and death."
Rizzo addressed the media after talking to the team and was visibly shocked by what happened.
"Jim told me pregame today [that] if we wouldn't pick up his option, then he wouldn't get on the team bus," Rizzo said. "I told him I thought he was doing a great job as the manager of this club. I'm the guy who hired him as the manager of this club. We have discussed his option being picked up several times during the season. I felt the time wasn't right for me to pick up the option [now].
"The timing of it, that he resigned at this time when we're playing so well and coming off a homestand that we should be celebrating ... I'm disappointed that this is a distraction. This is not thinking of the team first, it's thinking of personal things first. That's what disappoints me the most."
Riggleman repeatedly emphasized his displeasure with the one-year contract he's worked under throughout his managerial career.
He said picking up the option or even getting a longer contract is part of a commitment that the team could show its manager, a message that would resonate with the players, especially in an organization making strides like the Nationals have been over the past couple of years.
In the end, Riggleman said he was getting the message that he wouldn't be the team's guy in the future.
"I just wanted to have a conversation when we got to Chicago about it, and Mike said he's not ready to have that conversation," Riggleman said. "I said, 'I've got to give it up then. I'm obviously not the person that you all want to go down the road with, and I get that, that's OK.' We're talking about a relatively small commitment by today's standards to make a statement to the players, 'Hey, Jim is going to be here.' When they get the guy they want, it won't be on a one-year deal. Basically, when you're on a one-year deal, you're the interim manager."
There was a palpable sense of shock in the locker room as the players were dressing. Some didn't want to speak about the situation, but for those who did, it wasn't hard to figure out much this news blindsided them.
"Obviously, I'm as surprised as you guys were to see what happened at the end of the game, but whether I agree or disagree, I respect Jim's decision," said outfielder Jayson Werth. "I think I can say I'm disappointed, surprised for sure. It's a personal decision, and I respect it."
Reliever Drew Storen said he wasn't sure what to make of the unusual situation.
"It was very shocking," Storen said. "It's weird. I don't know how to describe it. I understand. He's got to take care of himself."
Despite the shock to the players and front office, Rizzo emphasized that he likes the success the team has showed of late and expects the club to continue to perform.
"We intend to build the Washington Nationals into a championship contender," Rizzo said. "Today's actions will not in any way deter us from those efforts."