The Mexican appeared primed to face the Liverpudlian for his WBA super middleweight world title, or British rival Billy Joe Saunders, who holds the WBO belt.
But Canelo now looks set to pursue a lucrative bout in Japan against Ryota Murata, who holds a secondary version of the world middleweight crown.
With the potential to open up a new market, in partnership with streaming platform DAZN, Gallagher admits his fighter is surprised by the manner in which he is likely to miss out.
“We can safely say that Canelo is doing what Floyd Mayweather did – he fights who he pleases and everyone just does what he says,” Gallagher told Sky Sports.
“Callum will be shocked and gutted, as Billy Joe will be. Everybody was waiting for the golden ticket but it has gone to Murata.
“I don’t think this will go down well in Mexico. We’ve been there with Liam Smith and everybody wanted Canelo vs Callum Smith. Even in Arizona the Mexican people were pushing for Canelo vs Callum.
“In September Canelo will have to fight a Callum or a Gennadiy Golovkin. The inquest will take place in Manchester today.”
Eddie Hearn appeared to suggest Canelo has indeed moved in a different direction, given his involvement with both Smith and Saunders, by announcing on Twitter that no talks have taken place with the pound-for-pound star.
Gallagher meanwhile is suggesting a domestic clash with Saunders is now unlikely too, despite suggestions from Hearn previously that the pair would meet if they both missed out on the ‘golden ticket’.
“We were already putting things in place to fight in April in America,” Gallagher remarked when the Saunders fight was proposed.