McManaman made a scoring substitute appearance against Nottingham Forest in the Capital One Cup earlier this season and followed that up with a brace in the recent reserve team game with Barnsley.
“Callum is working really, really well and I expect him to play a big part with us this season,” Martinez told the Wigan Evening Post.
Also impressing amongst the younger Latics ranks is England Under-20 goalkeeper Lee Nicholls who is presently out on loan with Northampton Town.
Martinez added: “Lee has really found his niche at Northampton. He kept a very important clean sheet in midweek, and he’s developed a very good relationship with his two centre-halves.
“He’s loving the challenge and he’s enjoying the experience."