LIMA, Nov. 6 -- Former Peru captain Claudio Pizarro has lent his support to one-time national teammate Paolo Guerrero, urging the striker to be patient as he fights to clear his name of doping allegations.

Guerrero has been provisionally banned for failing a doping test after Peru's 2024 World Cup qualifier against Argentina on October 5. Details of the substance were not revealed.

"I am with you and I will show my solidarity always," Pizarro, who has been capped 85 times for Peru's national team, said in an Instagram post.

"I know how professional you are; you are a model footballer and sportsperson. Be patient and don't worry. In time, things will work themselves out," added the 39-year-old FC Koln forward.

Last Friday, world football governing body FIFA said it was investigating the case after confirming that Guerrero gave an "adverse analytical result" to a routine doping test.

The provisional one-month ban rules Guerrero out of Peru's two-legged World Cup qualifying playoff against New Zealand on November 11 and 15.

Guerrero, a former Bayern Munich player, has missed Flamengo's last five matches in Brazil's Serie A championship as he struggles to overcome a leg muscle injury.

Peru and Flamengo medical staff have denied administering any illegal substance to the 33-year-old.