If it didn't coincide with sloppy mechanics and erratic stuff, sure! In all seriousness, he has a lot going on in his delivery, and historically it has been difficult for him to consistently execute. It's loud stuff, so he gets away with some scattershot, but when he has been bad it hasn't been situations you can chalk up to poor luck. Unless you are talking about the unfortunate circumstance of having high maintenance mechanics.
I don't really agree with that. At least not fully. 2012 I certainly do, he was awful and I'm sure a wreck mechanically.
But what's different about his 2010 and 2011 seasons, aside from ERA?
K-rate: 8.69 in 2010, 8.60 in 2011
BB-rate: 3.74 in 2010, 3.73 in 2011
HR-Rate: 0.81 in 2010, 1.27 in 2011
GB%: 48.8% in 2010, 47.2% in 2011
FB%: 35.0% in 2010, 33.3% in 2011.
If the mechanics were shaky, wouldn't you see an increase in walks? Decrease in strikeouts? Change in FB or GB rates? He did drop in velocity, so that's an argument to mechanics, but it didn't seem to effect his K-rate, BB-rate, or GB/FB ratio.
Where the numbers really indicate that he got lucky/unlucky between the two seasons:
LOB-rate (percentage of runners stranded): 76.5% in 2010, 65% in 2011
BABIP: .271 in 2010, .314 in 2011
HR/FB (percentages of flyballs that left the park): 5.1% in 2010, 9.3% in 2011
He stranded fewer runners in 2011, gave up more hits more often on balls in play, and more of the flyballs he gave up left the park. Everything else was pretty much the same. Unless there was a weird split that doesn't show up in the full season stats, like he was very good early and very bad late or something, the numbers don't scream out that there was any mechanical issue. Or perhaps more accurately, a mechanical issue that was the main cause of his higher ERA that season, instead of just some bad breaks or unfortunate results that were beyond his control.