The Belgian striker, who missed time earlier in the season with a hip injury, last scored in the Premier League against Newcastle United in September.
Yorke, who made over 200 appearances for the Villans in a nine-year spell at the club, told the team's official website: "Christian is a young guy. People should remember that. No-one knew much about him when he arrived. There is always a surprise package each season, and that was Christian.
"He was the main man and helped Villa when it looked dicey at stages. He turned it around for us with his goals. He started off this campaign really well with a couple at Arsenal and another at Chelsea. But he hasn't kicked on yet.
"All strikers go through periods where they don't score on a regular basis. You try to figure out where the next goal is coming. But he has everything. He has good height, good pace, he's a great header of the ball, he's good on the floor and he's a top target man. He's got the attributes to be great. I have been through what he's going through. He just has to keep the faith."
Villa host Manchester United tomorrow.