The PSG official has admitted that the transfer of the Brazil international might fall through after Adriano Galliani returned to Italy without an agreement in place
Both sides have been in talks about a summer move for the past few days, but Milan CEO Adriano Galliani returned to Italy on Wednesday without having reached an agreement.
Rossoneri president Silvio Berlusconi is believed to have the final say on a potential transfer, but Leonardo is not overly optimistic that the 27-year-old will make the move to PSG.
"The negotiations are still ongoing, but this situation shouldn't go on for too long," Leonardo was quoted as saying by La Gazzetta dello Sport.
"There are still many thing that need to be ironed out and need to be discussed. We will continue talks with Galliani. However, as things stand now, we might have to give up on signing Thiago."
Berlusconi previously stated that Paris Saint-Germain are willing to pay €46 million for the centre-back.