Four-time Tour de France winner Chris Froome (Team Sky) delivered an Adverse Analytical Finding for the presence of over two times the legal limit of salbutamol in his blood during his recent victory at the 2018 Vuelta a Espana.
The Adverse Analytical Finding resulted from samples taken after Stage 18, where Froome was part of a group that dropped Nibali and ended up taking 21 seconds on his Italian rival.
Nibali ended up finishing two minutes and 15 seconds down on the four-time Tour de France champion and stood on the second step of the podium in Madrid.
"Today the cycling world received bad news," Nibali said in a comment on Twitter. "If this is confirmed, no one will be able to give me the possibility to go on the top of the podium in Madrid. I'm sure time will give us the right answers."
Salbutamol is permitted by WADA rules, without the need for a therapeutic use exemption, when inhaled up to a limit of 1,600 micrograms over a period of 24 hours and no more than 800 over 12 hours.
Froome admits he had been using an inhaler to keep his asthma under control and that his asthma worsening was the reason for an increased dose. He did maintain that he had stayed under the limits set out by the Anti-Doping code.
It has been reported in Spanish publication Marca that Nibali also made comment on the specifics of the use of an inhaler, calling into question Froome's claims on innocent use.
"I have the same problem, but when it rains the pollen doesn't bother me and I don't use medication," Nibali said. "In that period it rained a lot in Spain, so it seems strange to me that Froome has had bad asthma."