Kevin-Prince Boateng's proposed move from Schalke to Sporting has broken down because of a disagreement over the player's image rights.
The Ghana international was suspended indefinitely by his club, alongside Sidney Sam, following a Bundesliga defeat to Koln in May.
Sam has since been welcomed back into the squad, but Boateng looked certain to join the 18-time Portuguese champions following negotiations this week.
However, Sporting confirmed on Wednesday that talks had fallen through due to failing to agree personal terms.
"Sporting Clube de Portugal, Futebol, SAD, announces that, after negotiations with Kevin-Prince Boateng, it was not possible to agree on his image rights," read a statement.
"Sporting SAD wishes Boateng both personal and professional happiness."