The trouble began when Marlins starter Chris Volstad hit Morgan in the right lower back with a pitch in the fourth inning. Morgan merely threw down his bat and ran to first.
"It was a hard play last night, and I can understand them wanting to get me back," Morgan said. "Once is good enough, but twice it's time to go."
On base, and with the Nationals down, 14-3, Morgan stole second base. And third. Then he scored on a short fly to the outfield.
"If they're not going to hold me on, I'm going to roll," said Morgan, calling it "garbage" that the Marlins didn't believe he should have been trying to steal in such a one-sided game.
"The game was a little out of whack, but it was only the fourth inning," he said.
The next time Morgan came to bat, Volstad threw a fastball two feet behind him. Morgan paused a moment, then threw away his bat and sprinted toward Volstad. Volstad dropped his glove as a charging Morgan threw a left hook that appeared to graze him.
Then from first base came Gaby Sanchez, who delivered a clothesline blow to Morgan that knocked him to the ground. Volstad rolled onto Morgan, but Nationals coach Pat Listach quickly threw him off and kept Volstad on the ground until being dragged off by several Marlins.
"It's not my first time," Listach said of his involvement in the fracas. "I'm not going to let it be six on one -- four infielders, a pitcher and catcher to our one guy. I'm going to defend our players any way I can."
The teams eventually separated as the umpires sought to restore peace. Meanwhile, Morgan was raising his arms in triumph to a jeering crowd.
Ejected were Marlins manager Edwin Rodriguez and pitchers Volstad and Jose Veras, along with Morgan.
Reliever Doug Slaten hit Sanchez with a pitch in the seventh inning, prompting his and Riggleman's ejections.
Almost lost in the chaos is the fact that left-hander Scott Olsen had one of the shortest starts of his career, giving up nine runs in 1 2/3 innings before being removed.
Olsen (3-8) was asked if he felt he should have been allowed to stay in the game longer to work out his problems.
"That's hard to ask for when you're getting killed," Olsen said.
The Nationals gave up their highest run total of the season, but 14 of those runs were scored in the first three innings. Olsen was peppered for six hits in the first inning and gave up another two, along with two walks, in the second.
"I had a good slider, but my fastball location was terrible," he said. "I've just got to do better."
The Nationals had taken a one-run lead in the first on Michael Morse's RBI single, but the Marlins countered with five in the bottom of the frame.
The Nationals came back for two runs in the second, on Morgan's sacrifice fly and Ian Desmond's double, then the Marlins scored another five.
The Marlins added four runs in the third. Then, of course, the game got out of hand.
Though down by 11 runs, the Nationals showed plenty of resilience in putting a scare of sorts into the Marlins. Justin Maxwell contributed two extra-base hits, and Wil Nieves hit a towering home run.
Also helping was Danny Espinosa, called up earlier in the day, who made his Major League debut in the bottom of the fifth inning at second base. Then, in the sixth, he got his first Major League hit -- an RBI double.
"I was a little nervous and had to slow myself down," Espinosa said.
Of the fracas, he said with a smile, "My heart was racing a little and then to see that happen ..."
The Marlins' feelings about Morgan may remain negative for a while, if third baseman Wes Helms' sentiment is any barometer.
"I can't stand when a guy shows somebody up or shows the integrity of the game up to the fans," Helms said. "There's just no place in baseball for that. In my opinion you are going to get what's coming to you if you do that.
"Tonight we had to show him we weren't going to put up with the way he was treating us."
Riggleman was asked if he is concerned that Morgan may be getting a negative and unjustified reputation that might affect how teams react to him.
"I'm pretty sure the Cardinals have some animosity toward Nyjer and the Marlins, too," Riggleman said. "But we'll protect him. If anybody takes liberties, we'll respond. Nobody is going to take a free shot."