The world players' union FIFPro said it had written to FIFA to request that Peru captain Paolo Guerrero, banned from the World Cup over cocaine contained in a cup of tea, be allowed to participate in the tournament.
FIFPro said on Twitter that it was "hoping for a breakthrough in the next 24-48 hours".
Guerrero had just completed a six-month ban after testing positive for cocaine, contained in a tea he drank, when the Court of Arbitration for Sport (CAS) increased it to 14 months on Monday.
UPDATE: @FIFPro has written to @FIFAcom requesting that Peru captain Paolo Guerrero be allowed to participate in the @FIFAWorldCup. We are hoping for a breakthrough in the next 24-48 hours. 🤞🏻 pic.twitter.com/nq5269UquD— FIFPro (@FIFPro) 20 May 2018
The extended ban, imposed after an appeal to CAS by the World Anti-Doping Agency (WADA), means the 34-year-old will miss next month's World Cup where Peru have qualified for the first time in 36 years.
CAS increased the ban despite accepting that Peru’s all-time leading scorer did not intend to enhance performance and that he had not knowingly ingested the substance.
FIFPro has already criticised the ban as being disproportionate and said that the WADA code had been imposed on football without properly consulting the players.
Tea infused with coca leaves, which are used as the raw ingredient in cocaine, is popular in Andean countries and a traditional treatment for altitude sickness