The Mexican Football Federation has told domestic players from Liga MX they will be dropped from the country's World Cup squad if they fail to report for a training camp and stay with their clubs instead.
The camp, starting Wednesday, 6 May, is taking place outside Fifa's designated international window and clashes with Liga MX play-offs in the top flight of Mexican football and Concacaf Champions Cup matches.
A deadline of 8pm local time (03:00 BST on Thursday, 7 May) has been given.
Last week, the federation (FMF) announced the 20 Liga MX players selected by coach Javier Aguirre to take part in the camp in Mexico City, with 12 players guaranteed a spot in the World Cup squad.
"All players must report to the High Performance Centre in Mexico City," the FMF said. "On the coaching staff's instructions, any player who fails to attend the training camp today will be excluded from the World Cup."
Mexico, who are co-hosts of this summer's tournament alongside the US and Canada, will announce their final squad on 1 June.
They play warm-up matches against Ghana on 22 May, Australia on 31 May and Serbia on 4 June, before starting their tournament against South Africa at Estadio Azteca on 11 June.
Toluca play Major League Soccer (MLS) side Los Angeles FC in the second leg of the Concacaf Champions Cup semi-finals on Wednesday, while Chivas de Guadalajara are preparing for their Liga MX play-off quarter-final on Sunday.
Toluca requested permission on Tuesday that the FMF release forward Alexis Vega and left-back Jesus Gallardo, angering rivals Chivas, who had already released five players; goalkeeper Raul Rangel, midfielder Luis Romo, United States-born midfielder Brian Gutierrez, winger Roberto Alvarado and forward Armando Gonzalez.
Toluca's request to hold back players to prioritise their Champions Cup semi-final, which they trail 2-1 on aggregate after the first leg, was seen as a breach of the agreement made with Liga MX clubs.
Chivas president Amaury Vergara wrote on X on Tuesday: “Agreements are valid only when all parties respect them. I instructed the Sports Directorate that our players report tomorrow at the club’s facilities.”
Chivas were beaten 3-1 by Tigres in the first leg of the play-off quarter-final last weekend.
On Wednesday, Chivas said: "We respect our players' desire to represent Mexico at the 2026 World Cup, and we will in no way be a factor that hinders that possibility, therefore they will report to the training camp on time and in the proper manner."
At a news conference, also on Wednesday after the FMF statement, Mexico head coach Aguirre said: "As you know, the statement is very clear: whoever doesn't come will be out of the World Cup. We can't be flexible, not at all."
He thanked Chivas and Toluca, adding: "Nobody has broken the agreement. So far the play-offs have been played without national team players. So far we are all in agreement with what we signed, what we discussed, what we saw – they have supported us unconditionally.
"I am here to explain that this is a unique project and that we are committed to it. Nothing extraordinary has happened, and everything is proceeding as planned, with the great support of everyone – fans, players, management and the press. We are all in the same boat, and I think it is important to tell you that."
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