The Premiership champions were expected to conclude a deal with the teenager having agreed a fee of £3 million with Motherwell.
However, negotiations with the player’s agent have reached an impasse and Celtic have now threatened to “move on”.
It is understood Turnbull was offered better terms than both Virgil van Dijk and Victor Wanyama when they first signed for Celtic. Van Dijk arrived from Groningen, where he played over 60 games. Wanyama was signed having played around 50 times for Beerschot in Belgium.
Turnbull made 30 league appearances in his breakthrough campaign at Motherwell last season, scoring 15 goals. Such was the 19-year-old’s impact he was named Scotland’s Young Player of the Year. Celtic have described the offer made to Turnbull as both “fantastic” and “magnificent”.
The Parkhead club released a strongly worded statement after it emerged talks with Turnbull and his representatives had broken down amid reports that the player had been offered to clubs in England.
Celtic pinpointed exactly where they felt the blame lay and stressed the club were unable to come to an agreement with “the player’s agent”. The midfielder is looked after by Pro Legal, a firm run by lawyer Liam O’Donnell.
It is believed Turnbull and his agent are investigating opportunities in England. Championship club Barnsley had initially entered the race to sign the midfielder along with Celtic.
Celtic said it was now up to the player – and his agent – to decide if they wish to accept their terms, which were relayed to Turnbull through his agent. The club made it clear there will be no further negotiating, on their part at least.
“Celtic FC was pleased to agree a record-breaking fee with Motherwell FC for David Turnbull and we have quickly followed this up with a fantastic offer to the player through his agent,” said a statement released through the club’s official Twitter account.
“Currently, we have been unable to come to an agreement with the player’s agent. Celtic is content that it has made a magnificent offer and it is now up to the agent and player to decide if the player wants to join Celtic. If not, we move on.”
The transfer would have been a record deal for Motherwell, eclipsing the £1.7m they received for Phil O’Donnell from Celtic in 1994.
Turnbull’s arrival at Parkhead was set to encourage a bid from Leicester City manager Brendan Rodgers for Callum McGregor. But as it stands it looks as though Turnbull won’t be augmenting manager Neil Lennon’s midfield options ahead of the new season in an episode that recalls Celtic’s failure to land John McGinn last summer.
Celtic were unable to agree a fee with Hibs and the player escaped their grasp and signed for Aston Villa for £2.75m. McGinn helped his new side into the Premier League via the play-off final where he scored the decisive goal.