The Aris FC striker is looking to revive his career after being dropped from national team consideration since Jose Manuel de la Torre took over in Mexico.
Nery has told Mexican press outlets that he is willing to come back to Mexico in an effort to revitalize his career, one that has dropped off significantly since leaving Olympiakos in 2007.
"My brother's been talking to Pachuca. He sent over an offer and now he's waiting for them to agree. That's the last I've heard of the issue," Castillo said to Medio Tiempo.
Castillo, currently playing for Greece's Aris FC, famously mulled over offers from Mexico, Uruguay and Greece's national teams before choosing to represent El Tri, then managed by Sánchez.
"Hugo knows I care about him, I know he cares about me and it's a nice thing that he's interested in me. He called me and now we're in the negotiation stage," said the former Manchester City player.
Bursting onto the scene with Mexico in the 2007 Copa América, Castillo put in a dream performance against Brazil and then helped push the CONCACAF team to a third-place finish.
Castillo was born to Uruguayan parents in the Mexican city of San Luis Potosí, where Nery Sr. was plying his trade. Nery also was eligible to represent Italy thanks to his mother's ancestry.
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