The Argentinian striker has struggled to adapt to football in England and is now set for a loan spell with Palermo in Italy.
“We’ve agreed a loan deal with Palermo and Mauro will go back to Italy, where he had a spell with Genoa, until the end of the season,” Martinez said.
“That was the reason why he wasn’t in the squad on Saturday.”
Boselli has already had loan spells with Estudiantes, from whom he joined the Latics, and also Genoa also based in Italy.