Barcelona are said to be filing an appeal with Fifa after football's governing body ordered them to de-list South Korean teenager Lee Seung-Woo, according to Sport.
The 15-year-old attacker entered La Masia in 2011 after being scouted as a member of the South Korea Under-13 team, and now trains with the Cadet B squad. His playing style has drawn comparisons to Lionel Messi, and his tweets in Korean and Spanish are followed by nearly 2,400 fans.
But in a rare decision handed down by Fifa following an anonymous complaint, the 21-time La Liga champions have been asked to de-register Lee after his signing was found to be in violation of Article 19 of the organisation's transfer regulations, which prohibit international signings of players under 18 years of age with few exceptions.
Although Barcelona has an academy in South Korea, Lee's treatment as an 'international signing' appears to be a result of his time at Gwangsung Middle School, whose football team are considered an academy club for Incheon United of the country's K-League.
The case of Lee, one of three South Koreans currently training at La Masia, is hardly considered unusual among top European clubs, leading to speculation that the anonymous tip came from a rival club or agent.
In a highlight video posted to the club's official YouTube channel in January, Lee was featured alongside fellow South Korean Jang Kyul-Hee as having scored one of the academy's best goals of the year.