Evans defense is about where A. McDyess's defense is.
All they can do with any proficiency on defense is to stand within 5 feet of the basket and grab some rebounds. However, neither one has been able to guard anyone adequately or play adequate team defense for at least a few years.
Though I will admit that when Evans was paired with Johnson Evans didn't look near as bad on defense just like Bargnani when he was paired with Johnson. Funny thing about that.