Kilmarnock have been charged after fielding an ineligible player in their 2-0 win over East Kilbride.
The Ayrshire side face a hearing on Thursday after breaching SPFL Rules and Regulations.
Daniel Armstrong was subject to a one-match Scottish FA suspension which was carried over from last season with Raith Rovers.
The former Hamilton Accies winger was introduced as a substitute in the 72nd minute of Killie's 2-0 win over Kilby in the Premier Sports Cup.
A Kilmarnock statement read: "The club can confirm we face a disciplinary hearing after being charged with breaching SPFL Rules and Regulations.
"Daniel Armstrong was included in the squad for Saturday’s Premier Sports Cup Group G game against East Kilbride at K-Park Training Academy while the player was subject to a one-match Scottish FA suspension in the competition, carried over from last season with Raith Rovers.
"Daniel entered the field in the 72nd minute of the game, which we won 2-0.
"The club would like to apologise to our supporters, East Kilbride and to the footballing authorities for this inadvertent breach of the rules.
"A hearing with the SPFL has been scheduled for Thursday, July 15 where the club will make representation.
"Until then, we will make no further comment."
Kilmarnock are likely to incur a points dedication and a fine as punishment and a precedent was set with Hearts in 2018 when they played Andy Irving against Cove Rangers.
East Kilbride could benefit from Killie's mistake and the K-Park side's match tonight against Greenock Morton is also in jeopardy.
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