Why is Eddy Curry so bad now?

Just in 2006-07, Curry averaged nearly 20 points and 7 rebounds per game in New York. He scored a total of 1,576 points that season. Just two years later, he scored 5 points total that season in 3 games for the Knicks. He now is struggling to start on the Timberwolves. Is this because of injury, personal reasons, or did he just simply start playing worse?