Lyon president Jean-Michel Aulas has admitted the club's summer transfer plans have been thrown up in the air after Atletico Madrid lost their appeal against a FIFA transfer ban.
Lyon had expected to sell Alexandre Lacazette to the Spanish club, with Aulas saying last month the striker would be allowed to leave for the "club of his heart".
The transfer would have generated significant funds for Lyon to re-invest into their squad, b ut after CAS on Thursday upheld a FIFA ban preventing Atletico from registering any new players until January 2018, that deal is now off.
"This is bad news and good news," Aulas said in comments reported by L'Equipe. "It was a very important financial transaction. Of course it changed everything.
"Alex had a good exit for Atletico, the club of his heart. I have not spoken to his agent or him as I was in Cardiff, but I had told Alex not to anticipate too much because in football you can always have disappointments.
"This calls into question the reciprocal commitments that have been made. We had advanced on a possible deal. We may have one more striker next year."
Atletico, along with city rivals Real Madrid, were handed two-window transfer bans in January 2016 for multiple breaches of global football's rules on the registration of under-18s and both clubs failed in their appeals to FIFA last September.
The two Spanish giants then took their cases to the CAS but, while Real saw their ban halved to one transfer window in December, Atletico announced on Thursday that the only reduction they had been given was regarding their financial penalty - down from £720,000 to £440,000.
The 25-year-old Lacazette, a product of Lyon's academy, has scored 127 goals in 274 appearances for the club.