Ange Postecoglou told Leigh Griffiths he has to work to win back the Celtic fans after he was booed by a section of them in the 6-2 friendly defeat to West Ham at Parkhead.
The Hoops boss made 10 substitutions in one go in the second half and 30-year-old striker Griffiths, recently cleared by police over allegations of sending inappropriate messages to two schoolgirls, elicited a negative reaction.
Police Scotland said it had established 'no criminality' after carrying out a 'full assessment' on claims Griffiths exchanged improper messages with a 15-year-old girl as well as another teen girl on social media.