The Suwon Samsung Bluewings player admitted his association with the worst scandal to hit the country's professional league since it was established in 1983 and Korean prosecutors were now looking into the case, the Yonhap news agency reported.
An unidentified former national team goalkeeper had confessed to his involvement in fixing last season's K-League matches at the weekend.
The report quoted a K-League official as saying that Choi, part of Korea's 2004 Olympic and 2007 AFC Asian Cup teams, was lured into attempts to throw matches by another player, who is among the 11 already indicted in the scandal.
Incidentally, Choi denied any wrongdoing in a press conference last month.
"If I had done anything wrong, I would've been summoned to the prosecution, and not here talking with you," he said.
League authorities have slapped life bans on 10 players - eight from the Daejeon Citizen team alone.
A player was found dead in a hotel room last month and media reports claimed a suicide note was found with reference to a match-fixing ring.
Three members of the top-flight military side Sangmu Phoenix have been questioned on suspicion of match-fixing, providing further evidence of how deep-rooted the problem was.
Players have until the end of this month to confess to their role and expect a lenient punishment.
The state-run sports bookmaker has stopped taking bets on games, while the government has threatened to stop funding any sports leagues found to be corrupt in any way.
