The Swedish Hockey Federation says Nicklas Backstrom was scratched from Sunday's Olympic gold medal hockey game because he tested positive for a banned substance.
A spokesman for the Swedish team says the forward will speak to the media later today.
Reports initially said he was suffering from a migraine headache.
The Swedes lost the game 3-0 to Canada.
Backstrom, who had been the Swedes' No. 2 centre in the absence of Henrik Zetterberg and Henrik Sedin, had four assists in the first five games of the tournament.
Backstrom was not on the ice for pre-game warm-ups but was listed on the official lineup sheet.