FIFPro and the captains of Australia, Denmark and France backed Guerrero, pointing out that CAS itself recognized that he did not seek to gain an advantage.
Before the match that sealed Peru's first World Cup appearance for a generation in November 2017, the players ran out in Lima's national stadium wearing T-shirts baring the slogan, "Fuerza Paolo".
"While Guerrero has won a temporary reprieve from the Swiss federal court, it is unfortunate that he has to endure such a protracted legal wrangle that is still not over". "There are no impossible dreams, as it has been proved that when Peruvians are united, everything is possible".
On Thursday, the Peruvian FA revealed that there will be a further appeal to the Swiss Federal Court, which will, at the least, delay any suspension until after the World Cup has taken place.
Cas had imposed the ban this month, upholding an appeal by the World Anti-Doping Agency.
"Gianni Infantino expressed his deep understanding of Guerrero's disappointment in not being able to join the Peruvian squad at the 2018 FIFA World Cup", said a short FIFA statement last week.
Last month Guerrero gained the support of all three captains of Peru's Group C rivals - including Mile Jedinak, France's Hugo Lloris and Denmark's Simon Kjaer - who co-signed a letter urging Federation Internationale de Football Association to lift the suspension and allow him to take his place in the side. The panel decided a ban to January 2019 was an "appropriate sanction ... in light of Mr Guerrero's degree of fault". He then returned to play for Brazilian club Flamengo.
Earlier on Thursday (Friday NZT), CAS - which based less than a kilometre from the federal court in Lausanne - issued a statement saying it would not object if Guerrero was cleared to play in Russian Federation.
But WADA appealed the length of the suspension to the CAS.