The referee for Saturday’s MLS game between Inter Miami CF and Orlando City SC has been replaced by the Professional Referee Organization (PRO) after pictures emerged on social media of the original assignee, Guilherme Ceretta, wearing an Inter Miami jersey.

Ceretta has been replaced by Jaime Herrera, according to PRO’s weekly announcement of MLS referee assignments. Ivan Cid Cruz replaced Herrera as the fourth official with Bruno Rizo and Regis Cardoso remaining as the match’s assistant referees. The pictures were first revealed by the X account @MLSRefStats.

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A spokesperson for PRO, which assigns referees to officiate matches in MLS, confirmed to ESPN: “Referee Guilherme Ceretta was removed from the game due to a potential conflict.”

The change comes at an awkward time for PRO, which is engaged in a lockout of referees belonging to the Professional Soccer Referees Association (PSRA), the union attempting to negotiate a new collective bargaining agreement with PRO. In the interim, PRO has been using replacement referees pulled from other professional leagues as well as the collegiate and youth ranks.

“As long as the focus stays on fighting organized labor rather than utilizing the most well-trained, experienced officials in the league, you will continue to stray from promoting the very best of the game,” PSRA president Peter Manikowski said in a statement to ESPN on Saturday.

“Sporting integrity provisions are in our CBA and we take them very seriously. But when the league perceives these professional officials are asking for too much, the first thing to go is the sporting integrity backstops like rigorous fitness testing, medical checks, background checking and anti-doping.

“The sport will ultimately suffer.”

Talks on a new CBA between PRO and the PSRA appear to be at a standstill. The previous CBA expired on Jan. 15, though the two sides agreed to extend the terms in a bid to continue negotiations. On Feb. 15, the PSRA membership overwhelmingly rejected a tentative agreement reached between PRO and the PSRA executive board, with 95.8% of the PSRA union membership voting against ratification. PRO responded the next day by locking out the PSRA referees.

The PSRA has since offered a counterproposal, which PRO not only rejected, but responded by saying that the terms of the tentative agreement amounted to its best offer. In a letter from PRO general manager Mark Geiger to the PSRA membership, Geiger added that if the PSRA didn’t approve the terms contained in the tentative agreement by March 11, its next offer “will include less favorable terms in some areas.”