The Belgium international has not featured for the Midlands since April after he suffered a ruptured Achilles injury.
Over the international break, the 23-year-old has been building up his fitness and Lambert has hinted that the forward could return to action against the Toffees at Goodison Park.
"Christian is pushing to start," Sky Sports News quotes Lambert as saying. "I said at the time that the international break would come at a good time for him, because that gave him another couple of weeks to train with the team.
"We had a [behind-closed-doors] game here against Leicester that he scored in so that gave him a lift as well."
Villa have lost their last three league games.