David Wheater played as a trialist as Kilmarnock lost 3-0 to Dinamo Bucharest.
Angelo Alessio saw his team fall to their first defeat in Wednesday night’s friendly in Marbella.
The former Bolton captain, 32, played in the second half.
Dinamo went ahead in the 11th minute through Florin Bejan and sealed the win, after Alessio had made a string of changes, through goals from Dan Nistor and Andreas Mihaiu.
Wheater is a free agent after leaving Wanderers after their relegation to League One.
Former Preston and Fulham midfielder Ben Pringle and Finnish international striker Tim Vayrynen also featured in the game.
Kilmarnock boss Alessio now has to decide whether he is going to deal any of the trio in before tomorrow night’s Europa League deadline.
Alessio, however, can add one wildcard signing to his group before next Thursday’s first qualifying round clash away to Connah’s Quay Nomads.
