Action must be taken to prevent violence at football grounds and ensure player safety, according to PFA Scotland.
A bottle thrown from the stands narrowly missed Scott Sinclair as the Celtic winger prepared to take a corner during their Scottish Cup win over Hibernian at Easter Road on Saturday.
It is the latest in a rising number of incidents the union has called "alarming".
Fraser Wishart, chief executive of PFA Scotland, said: "After this weekend's incidents at Easter Road, we stress again that the throwing of objects at players, violence or any form of verbal abuse directed towards players must be taken seriously and we trust that the authorities will take the appropriate action to ensure that this dangerous practice is stopped.
"The continuing rise in incidents of this nature at football grounds across the country is alarming and must be addressed with the greatest of urgency.
"On the field, our members have been subjected to racist and sectarian abuse, physically assaulted and had coins and now a bottle thrown at them.
"Any form of abuse - physical or verbal - is wholly unacceptable and it is of paramount importance that something is done before someone is seriously hurt or maimed.
"The football pitch is a player's place of work and it is not unreasonable for a player, like any other employee, to be able to work with the knowledge that their workplace is indeed a safe environment, free from violence and discrimination and that their health and safety is not at risk."