A drunk driver who hit a 25-year-old South Korean soccer player and inflicted injury that forced his retirement appealed his sentence of four years in prison, Jeju District Court said Wednesday.

According to the court, the 36-year-old defendant filed for appeal on Tuesday, despite the sentence being lower than the five-year jail term requested by the prosecution. It is yet unclear what his reasons for the appeal were.

The defendant, while driving under the influence, struck another vehicle carrying Jeju United FC goalkeeper Ryu Yeon-su on Oct. 18, 2022. Ryu's injuries were so severe that, despite rehabilitation, he was not able to overcome them, and he announced his retirement in November of 2023.

Ryu joined the Jeju-based team in South Korea's division 1 K League in 2020.

In his final statement to court last month, the defendant said that he would "get down on his knees and apologize if given the chance." But Ryu said on Jan. 17 that the defendant never reached out to him or tried to apologize.

"I was furious when I heard what (the defendant) said. I would have accepted his apology," he said while appearing on the tvN talk show "You Quiz on the Block."

After the court announced the sentence last week, Ryu's mother expressed her disappointment with the ruling, saying, "my son has been crippled for life, but (the defendant) can go back to his own life after four years in jail."

Ryu's legal representatives said they will decide whether or not to appeal the case after reviewing the verdict.

The Ryu's tragic accident sparked furor among soccer fans in the country, with the Jeju United's official supporters' group Gyulcano petitioning for a harsh punishment for the drunk driver.