The World Anti-Doping Agency (Wada) has lodged an appeal to the Court of Arbitration for Sport (Cas) over Paolo Guerrero's six-month doping ban as it seeks a stricter punishment for the World Cup-bound forward.
Guerrero's initial one-year suspension reduced on appeal
The Fifa Appeal Committee issued a decision in December 2017 that reduced an initial year-long suspension, meaning that Guerrero - having tested positive for cocaine in October - would be available in time to captain Peru at the World Cup in Russia come June.
Wada want longer ban, Guerrero out to have it quashed
But Wada wants to see his ban extended back to one to two years - a sanction that would leave the South American nation, at the World Cup for the first time since 1982, without their star man.
Flamengo front man Guerrero, however, has also appealed as he seeks to have the ban removed completely.
Two arbitration procedures have been opened, with both to be referred to the same panel ahead of a hearing at the Cas headquarters on May 3.
Peru face France, Denmark and Australia at World Cup
Peru have been drawn against France, Denmark and Australia in the finals, having qualified through a play-off against New Zealand in which they were without Guerrero, who scored five times in the Conmebol stage.