Ian Madigan and Jamie Heaslip have been nominated for the EPCR European Player of the Year.
Selected by a panel of rugby experts including European Cup winner Alan Quinlan and Challenge Cup winner Dimitri Yachvili, the longlist includes 15 players who have performed outstandingly during the 2014/15 season to date.
Last season's winner Steffon Armitage is nominated once again, along with Northampton Saints' George North and Fritz Lee of ASM Clermont Auvergne who made the 2014 longlist.
Saracens' prolific try scorer, Chris Ashton, who made last season's five-man shortlist, is also included on this occasion.
Clermont, who clash with Saints in the Champions Cup quarter-final in April, have four players in the list in total.
The panel of judges will have the option to consider additional players who make major contributions during the knockout stages of the Champions Cup and Challenge Cup before announcing a five-man shortlist following the semi-finals with the overall winner named directly after EPCR's finals in London in early May.
EPCR European Player of the Year 2015 longlist:
Nick Abendanon (ASM Clermont Auvergne)
Steffon Armitage (RC Toulon)
Chris Ashton (Saracens)
Jamie Heaslip (Leinster Rugby)
Juan Imhoff (Racing Metro 92)
Jonathan Joseph (Bath Rugby)
Fritz Lee (ASM Clermont Auvergne)
Camille Lopez (ASM Clermont Auvergne)
Ian Madigan (Leinster Rugby)
George North (Northampton Saints)
Jamie Roberts (Racing Metro 92)
Aurélien Rougerie (ASM Clermont Auvergne)
Nicolas Sanchez (RC Toulon)
Dimitri Szarzewski (Racing Metro 92)
Billy Vunipola (Saracens)