Being poor at your job for a year is a long time in any profession, some may argue it's been longer.
That's the bottom line of it really. I know he's had problems with injuries etc, but you can still perform well at your job in difficulties circumstances and I don't think you can say he has. In fact he has only made matters worse.
If he can only produce results when it's all sunshine and roses then I don't think that's good enough.