Glentoran say they are "pursuing a full and transparent investigation" into the events following Bobby Burns' injury against Crusaders on Saturday.
Burns received lengthy treatment at the side of the pitch before leaving on a stretcher after colliding with an advertising hoarding at Seaview.
The game continued while the 24-year-old received treatment.
Burns revealed that he had broken his jaw in two places but he did not have any major neck or back damage.
A statement from Glentoran chairman Colin Jess said: "No consideration was given to his safety or dignity, nor the potential of further injury from the game continuing.
"While Bobby has undergone an operation and is now recovering, for some time his condition was considered extremely serious.
"It is essential that protocols are put in place to ensure this doesn't happen again and that no other player from any club should be treated in such a neglectful way.
"I am sure that the NIFL family will agree that this incident should be fully investigated and that all players safety is of paramount importance in such circumstances."
The Northern Ireland Football League, the Irish FA and Crusaders have been contacted for comment.