Keita Balde Diao moved to Spartak Moscow, but has been suspended for three months over an anti-doping test violation while he was still at Cagliari.
The incident occurred on April 3, 2022, after Cagliari were beaten 5-1 by Udinese at the Dacia Arena.
Although the sample showed no signs of banned substances, the Senegal international is nonetheless penalised for breaking the strict protocol around the test.
It means the former Inter and Lazio striker must sit out a 90-day ban in all official matches that will expire on December 5.
Until then, Keita cannot play for his new club, Spartak Moscow.
The 27-year-old forward was released as a free agent by Cagliari for the move to Moscow on August 26, where he made just one substitute appearance in the 2-1 home defeat to Zenit St Petersburg.
His other career clubs include Monaco and Sampdoria.
He made 185 Serie A appearances, scoring 41 goals and contributing 21 assists.