An American baseball player competing in the South Korean baseball championship series apologized on Wednesday for refusing to wear a mask during official pregame and postgame functions.

Aaron Altherr of the NC Dinos skipped the award ceremony and his postgame press conference on Tuesday, after being named the Player of the Game in the Dinos' 5-3 victory over the Doosan Bears in Game 1 of the Korean Series.

Altherr hit a three-run home run at Gocheok Sky Dome in Seoul, but told the club and the Korea Baseball Organization (KBO) that he wouldn't be able to keep his mask on for the events because he would have trouble breathing.

Under the league health and safety protocols during the coronavirus pandemic, players must don masks for pregame and postgame events. They also must wear masks during the game, except for the time when they're on the field.

Altherr was also photographed without a mask during the Korean Series opening ceremony on Tuesday.

The KBO fined Altherr and three other NC players 200,000 won ($180) each for their violations. Under the league rules, players receive a verbal warning for their first offense and are fined for their next offense. A third offense results in a 1 million won fine.

The KBO said Altherr and his three teammates, whom it declined to identify, were the first players to be fined for failing to wear masks.

The mask controversy put a damper on the Dinos' first Korean Series win in franchise history. A Dinos official told reporters Wednesday, prior to Game 2, that Altherr expressed his contrition.

"He recognizes the gravity of the situation," the team official said. "He said he was sorry to have caused trouble, and said he will now respect and follow health protocols."

NC manager Lee Dong-wook said in his pregame media session that he will make sure Altherr will join the rest of the team in adhering to those rules.

Asked if Altherr is particularly difficult to control, Lee said, "No, not at all."

Drew Rucinski, the winning pitcher from Game 1, was also asked about the situation in his pregame press conference, and the American pitcher said his and the team's focus is solely on baseball.

"We're here in the Korean Series and that's the first question I get. I'm not real thrilled with that," Rucinski said. "Our guys are focused on baseball. (Altherr) is focused on baseball. He's focused on hitting the baseball every day out there and playing great defense. We're going to play baseball and that's our business."

Altherr didn't respond to a text message from Yonhap News Agency sent earlier Wednesday seeking comment. (Yonhap)