Skysports.com understand Cardiff and Norwich are leading the chase for unsettled Celtic forward Derek Riordan.
Riordan is thought to be considering his future at Parkhead after failing to establish himself in Gordon Strachan's plans.
The 22-year-old has hardly had a look in at Celtic since arriving from Hibernian last summer, making just four appearances so far this season.
The news has alerted a number of clubs to Riordan's possible availability as they weigh up moves for when the transfer window reopens in January.
Cardiff have held a long-term interest in Riordan and tried to sign the Scottish international before he made the move to Celtic.
Bluebirds boss Dave Jones is keen to bolster his squad in January as he looks to maintain their push for promotion and he may renew his interest in Riordan.
Norwich are set to rival Cardiff for Riordan with Canaries boss Peter Grant confirming his interest in the versatile performer last month.
It remains to be seen if Celtic will consider any move for Riordan as they have to contend with the extra demand of the UEFA Champions League in the New Year.