Despite the 25-year-old scoring nine goals to help Wigan survive in the Premier League last season, Martinez has claimed that his team have adapted well to life without N'Zogbia.
"You can't replace a player like Charles," Martinez told a press conference. "Instead you have got to change how you play.
"We are creating more chances but that is down to playing a different way. Other players have stepped up and taken the responsibility.
"We have found the right mixture in our attacking play and the solutions to be an effective unit going forward."
McLeish spent £9.5m to take N'Zogbia to Villa Park.