N'Zogbia has been out of action since rupturing his Achilles on holiday last summer, and Lambert has dismissed suggestions that he is choosing not to bring the French winger back into the first-team squad.
"It's just in my opinion he isn't ready for training in the first team at the minute," the Scot told members of the media. "It's too much for him.
"He's still really short of match fitness. You can do all the training you want, you can work with the fitness lads, but for this level of football you've got to get yourself up to top level.
"I don't think he's ready for anything like that at the minute."
N'Zogbia joined Villa from Wigan Athletic for £9.5m in the summer of 2011.