Brewer is playing very well and has been a very positive contribution.
That said, I find it really hard to be quite so critical of Fields due to the medical information that was revealed earlier this season.
http://blogs.thescore.com/raptorblog...-and-anderson/
As for why Fields needed that surgery and what it meant, it was essentially to treat what is called a "nerve compression".
http://orthoinfo.aaos.org/topic.cfm?topic=a00069
Essentially, what was happening to Fields is that in his shooting arm, he would attempt to use his shooting arm and the nerve along his arm would compress at the elbow, this would trigger a reflexive response (like a doctor hitting your knee) that would cause his hand to involuntarily grip or claw towards the end of this stroke.
Also, general compression in the nerve can cause numbness and tingling in the arm, but more importantly can affect the ability to perform fine motor movements with the arm and hand (like snapping a ball off the wrist accurately).
In an interview with the National Post, Landry spoke about his surgery.
http://sports.nationalpost.com/2012/...after-surgery/
This condition can be intermittent for long periods of time and not create pain, so it is easy to miss in terms of a diagnosis until it becomes serious. The effects can be as minor as tingling and random reduction in motor function and co-ordination with the associated limb and hand.
It is quite possible that Landry could have been suffering this condition all last year without he or the team physicians noticing it. It's also quite possible that this condition was degenerating, IE, the compression was continuing to worsen until he finally noticed it this year during the training camp.
It is impossible to know whether last year was truly because Landry sucked, or he was being physically impaired without anyone (including him) knowing. It will be interesting to see what happens when he returns to play post-surgery.