Michael Fleming, who plays for Cowdenbeath under-19s, allegedly wrote a number of comments during the match on Wednesday. He later posted an apology and his profile has now been deleted.
Cowdenbeath FC said the comments were “unacceptable” and the player had been disciplined.
A club statement said: “He is aware that his conduct is not acceptable. He has apologised unreservedly for his conduct.
“Cowdenbeath Football Club does not condone and will not tolerate any form of sectarianism. The club will remind everyone connected with it that sectarianism in any form is not acceptable.”