Peru striker Paolo Guerrero has been provisionally suspended for 30 days after failing a doping test.
The Peruvian Football Federation says in a statement on Friday that FIFA's disciplinary committee made the decision after Guerrero tested positive on Oct. 5 after the World Cup qualifying match against Argentina.
The federation did not disclose the banned substance.
If the decision is upheld, Peru will miss their main striker for both matches against New Zealand in the playoff this month for a place in the World Cup in Russia next year.
The federation said it "believes the facts will soon be clarified and this issue will be permanently solved."
Sources close to the player told ESPN Brazil -- who reported the ban was for a "social drug" -- that Guerrero, a player for Rio de Janeiro giants Flamengo, "didn't know anything" and was "surprised by the news" once relayed to him on Friday.
Earlier Friday, the head of doping control of the Brazilian Football Confederation said Guerrero could still provide evidence that he did not take prohibited substances without warning Peru and Flamengo.
"If Guerrero has justification for this and that justification was offered before the match against Argentina, it is not a doping case," Fernando Solera told channel SporTV.
Solera also said Flamengo showed evidence that Guerrero did not take any illegal substances during his time with the Brazilian club.
Guerrero's lawyers said the player has denied using any type of banned substance.
Four players underwent mandatory doping tests following the match in Buenos Aires: Paulo Dybala and Alejandro "Papu" Gomez of Argentina, and Guerrero and Edison Flores of Peru.
Guerrero scored six times in South American qualifiers and led Peru to fifth place.
Peru's first-leg playoff match against New Zealand will be played at Westpac Stadium on Saturday, Nov. 11. The second leg will be played at the Estadio Nacional de Lima in Peru's capital on Nov. 15.
The Associated Press was used in this report.