Alexander Buttner's proposed move to Southampton from Vitesse Arnhem has stalled, according to the Dutch club.
The 23-year-old defender had been linked with a move away from the Eredivisie side this summer, and last week it was announced he would be joining the newly-promoted Barclays Premier League outfit.
However, there now appears to have been an intervention by a third party which looks set to hold up the deal. A statement by Vitesse Arnhem read: "The transfer of Alexander Buttner to Southampton FC is now uncertain."
It continued: "Last Friday, Vitesse came to an agreement with Southampton about the transfer of Alexander Buttner to the Premier League club. Because Buttner himself also agreed on his personal conditions with Southampton FC, Vitesse was in the supposition that the transfer was a fact, with the proviso that Buttner would pass medical examination.
"However, this weekend the player informed Vitesse via his agent that a third party had a supplementary demand towards the club. Vitesse made it clear to the player that it would not comply with that demand, since it was applied in retrospect and Vitesse will not be pressurised.
"Vitesse is disappointed about the course of things, all the more because Vitesse negotiated with Southampton FC on the player's request. Southampton FC has taken up an absolute correct position and is not to blame for the possible fall through of the transfer. Vitesse have also tried all possibilities to keep the set deal going through."
Buttner, who can also operate at right-back, came through the youth system at Vitesse.
The Doetinchem-born player made 107 appearances for the Dutch club and had been named in Holland's provisional 36-man squad for Euro 2012, although did not eventually go to the finals.
Southampton were unavailable for any immediate comment.
Meanwhile, Saints also look set to wait for the ratification of the proposed transfer of Rangers captain Steven Davis after international clearance was put on hold by the Scottish Football Association.