Burnley are seeking a response from bookmakers Ladbrokes to a message on social media which contained a rude gesture towards players Chris Wood and Charlie Taylor.
Ladbrokes, who are the club's "official UK betting partner" and sponsor the Cricket Field Stand at Turf Moor, made the post in the wake of Burnley's loss to Leeds in the Carabao Cup on Tuesday.
Former Leeds player Wood scored a late equaliser as his side twice came back from a goal down, only to lose 5-3 on penalties after extra-time.
Following the game, a message on Ladbrokes' official Twitter account was addressed to Wood and Taylor, followed by an image of a raised middle finger and the words: "Yours sincerely, Leeds fans #LUFC."
A spokesman for Burnley told Press Association Sport: "The club are aware of the problem. We have contacted Ladbrokes and are awaiting a full response."