According to reports in Brazil, 33-year old Ronaldinho has suffered a serious thigh injury in training that threatens to end not only his season for Atletico Mineiro, but also his inclusion in the Club World Cup squad.
ESPN Brazil reports that he suffered a 'grade 3 injury to the adductor muscle of the right thigh, with the total rupture of the tendon'.
Since joining European football with Paris St. Germain in 2001, Ronaldinho has enjoyed any successful spells with Barcelona, Milan and Atletico Mineiro - as well as winning World Player of the year in 2004 and 2005.
He was widely considered to be the world's best player while playing for Barcelona, and is known for his skilful style of play.
Since moving back to Brazil, Ronaldinho has enjoyed a small revival in form and fortune, having been called up by Brazil manager Luis Philippe Scolari for Brazil's World Cup warmup games.
He won the Copa Libertadores last season with current club Atletico Mineiro, but this latest injury threatens to disrupt his participation in the FIFA Club World Cup. The other clubs taking part include Monterrey, Auckland City, Raja Casablanca, Bayern Munich and the winners of the AFC and CAF Champions Leagues.
There has been no official announcement from Mineiro, who are expected to wait on the results of several MRI scans before releasing a statement.