Liverpool and Portuguese international full-back Abel Xavier has been struck down by a mystery virus, according to the Merseyside club.
Manager Gerard Houllier confirmed that the player is undergoing tests to determine the root of the illness.
"It is some kind of virus," said Houllier. "We're doing all the tests but have not found the cause".
Xavier hasn't played since the Merseysider's 2-2 draw with Newcastle on September 2nd.
Liverpool were without German defender Markus Babbel last season after he was struck down by the debilitating and potentially fatal Guillain-Barre syndrome.
