Talks between Leicester City midfielder Gokhan Inler and FC Schalke have stalled, the German club's coach Andre Breitenreiter has said.
Inler, 31, was a Schalke target during the 2015 summer transfer window but he opted to join Leicester, where he has found regular first-team football hard to come by.
The Switzerland international has spent most of the season on the substitutes' bench, starting three matches for the Foxes.
In recent weeks, he has been linked with Schalke once more, and last Sunday Inler confirmed in Blick that "a transfer is certainly possible."
However, the Royal Blues, who want to sign Inler on loan, are beginning to running out of patience,
"We are in talks, but the devil is in the details," Schalke 04's sporting executive Horst Heldt said during a news conference on Wednesday. "It's a fact that we have to be convinced of the complete package."
Schalke coach Breitenreiter doubts Inler's heart is behind a possible transfer.
He told kicker: "I don't think it's a financial problem. The player has shown interest, but he's not here yet. It raises the question whether he wants to join FC Schalke 04 by all means."
Schalke are currently preparing for the second half of the Bundesliga season in Orlando, Florida, and on Wednesday completed the signing of Dinamo Kiev midfielder Younes Belhanda.
The 25-year-old Morocco international has joined the Bundesliga club on a six-month loan, and the contract does not include an option to buy when the deal ends in the summer.