Allardyce feels that the former Olympiakos winger is not fully focused on his football at the moment following the summer euphoria and has urged the 31-year old to get back down to earth.
The Bolton boss was particularly critical of the performance that Giannakopoulos put in as a second half substitute during Saturday's defeat to Fulham when coming on for the injured Henrik Pedersen.
"We brought the 'Greek God' on. At least that's what he thinks he is at the moment,"
"He'll have to get back down to earth like the rest of us and start grinding these Premiership games out." Allardyce said