The Latics chief initially wanted to bring in the Ecuadorian on loan, but with his attempts to do so having failed he is targeting a permanent switch.
After slipping into the Premier League relegation zone, the Spaniard is all too aware of a need to strengthen his squad.
A wide, creative player is believed to be a top target, which has seen him highlight Montero.
The 23-year-old has reportedly told his club Monarcas Morelia that he wants to leave, but the Mexicans are far from keen to allow him to depart on the cheap.
Martinez was thought to have lined up Republic of Ireland wide-man Aiden McGeady as his main target, but he has been priced out of a move.
Spartak Moscow are believed to value him at around £5m, a fee Wigan could match, but the DW Stadium-based side would be unable to match his wage demands.
Montero is a more cost-effective option, with a sum of around £3m thought to be enough to tie up a deal.
Prior to moving to Mexico, Montero spent a long period of Spain.
He joined Villarreal in 2009, forcing his way into the first team by 2010.
However, with first-team chances limited he joined both Levante and Real Betis on loan before signing with Monarcas Morelia.