The Ecuador international had been strongly linked with a move to Wigan after being compared to his compatriot Antonio Valencia, who had previously enjoyed success at the DW Stadium.
Wigan reportedly wanted to sign Montero on an initial loan deal, while Real Betis also launched a bid for the 23-year-old.
However, Morales says Wigan's offer was not good enough for a player who only joined Morelia from Villarreal last summer.
"Five days ago we had been approached asking for the player," Morales told the Mexican media. "We spoke with him, he knew about it, but the offer wasn't good.
"We thanked Wigan but we decided not to accept it, and that's all. Then, there wasn't a new proposal.
"The situation stood there, some days went by and, with Montero, we were clear that the proposal wasn't worth it.
"Wigan wanted the player for six months, but what they offered was much less than what Betis offered, so we decided not to take it.
"Montero is a player of great quality and we are not going to give him away just like that. He is one of the most important players of our team."
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