You should overlook it. In the past three seasons 4 of the above mentioned catchers only caught around 40 innings of Lester. In 2011 Lavs only caught 6 games. I think Cash only caught Lester for a two year period for a whopping 4 games. Is it fair at all to use such small sample sizes to compare to full time catchers? I think it is only fair to look at his full time catchers year by year that are behind the plate for 140 plus innings.
2007 Tek. 4.74
2008 Tek. 3.06
2009 Tek. 3.92
2010 V Mart. 3.64
2011 Salty 3.77
Now looking at the numbers to that point Salty was not his best or worst year, Those both belonged to Tek. up to this point, but you can see Salty had a full season with Lester that produced an era consistent with all the other catchers. Is someone going to deny that?
So yes 2012 Salty and Lester had a bad era, but if the era's above are correct..... and they are, then 2012 is Lester' s fault. If Lesters 2012 era was so much to blame on Salty then one would expect all the pitchers to have done worse with Salty..... and that simply was not the fact in 2012, as some pitchers pitched better to Salty. I know nobody likes Salty, and I don't think the guy is a very good player, but to compare his CERA to other catchers that only caught a handful of games is not fair or accurate.