Lambert has reassured the 28-year-old that his lack of first team action is due to the form of his team-mates rather than anything he has done wrong.
"I've spoken to him and I had a good chat with him," he told Villa's website.
"He is an experienced player and has done really fine since he's been here.
"You don't want people to sit and be happy when they are not in the side. You want them to be unhappy. He couldn't get in because Charles was playing extremely well.
"He wasn't fit for last week. He is fit now. He has trained this week so he is back in the fray."