Rangers are reportedly set to sign Mexican ace Carlos Pena.
The Portuguese coach worked with Crosas at Santos Laguna.
Crosas played under prospective Glasgow Rangers boss Caixinha, another ex-Celtic employee, in Mexico, and has advised the Portuguese about moving to Ibrox.
Pedro Caixinha remains the favourite for the Rangers job.
Celtic beat Malmo 3-2 in the first leg of their Champions League play-off on Wednesday night.
Could a club Celtic are in partnership with help develop some of the Bhoys current or future players?
Ex-Celtic midfielder Marc Crosas poked fun at Rangers after their defeat to Motherwell on Sunday.