Orioles manager Buck Showalter shrugged off the impact of the ejection, saying Matusz would have faced only one more hitter anyway.
"He wouldn't have pitched the next inning," Showalter said.
Matusz entered the game in the 12th with the score 0-0 and retired the first two batters before new Marlins manager Dan Jennings approached home plate umpire Jordan Baker. Baker and crew chief Paul Emmel then went to the mound to inspect Matusz's arm.
"I went out there and told the pitcher I was going to touch his right forearm," Emmel said. "That's where he was touching before he went to the ball. I detected a foreign substance, so the pitcher was ejected."
Showalter joined the conversation with no argument.
Matusz declined to say much about it.
"We're not going to address the issue right now," he said. "Obviously I have my own personal opinions about the issue, but right now with emotions running high we're going to let this settle and address questions at a later time."
Jennings said the Marlins noticed Matusz using a suspicious substance.
"We saw something shiny on his arm," Jennings said. "We watched a couple of pitches to make sure he went to it. By their opinion there was a foreign substance there, they made their decision."
The Marlins broke an eight-game losing streak and improved to 1-8 on their homestand. Jennings earned his first career victory in six games as a manager, then received a dunking from his players in the nightclub swimming pool adjacent to the clubhouse.
Jennings was unable to pinpoint who dunked him in the pool.
"No, the shaving cream pretty well blocked my vision," he said with a laugh. "It's the best, dirtiest bath I've ever had."
The Associated Press contributed to this report.