The Chicago Tribune certainly promoted the belief that Prior's mechanics were "flawless", but isn't this now widely seen as incorrect? I know that Prior's name is usually mentioned now as an example of flawed mechanics leading to injury.
There's still a lot of debate about it. The general consensus I've heard recently though is that his career was derailed not due to his pitching mechanics but due to his freak accidents. A lot of the arguments that cite Prior as an example of poor pitching mechanics usually don't have much actual evidence to support the claim.
