Viktoria Plzen defender David Bystron tested positive for a banned substance following a Champions League match and could now face a ban of up to four years, the Czech club have confirmed.
Bystron was tested following Plzen's 1-0 win away to BATE Borisov in Group H on November 23, and was found to be positive for an undisclosed banned substance.
"The B sample has confirmed the result from Minsk,'' said Plzen spokesman Pavel Pillar on the club's website.
"The information we have received from UEFA contained only this short notice, with detailed analysis due to arrive next week. At the same time, we also expect information on how to proceed, including the date of disciplinary hearings.''
Plzen finished third in Group H behind Barcelona and AC Milan, securing a place in the Europa League.