With catchers, it's all about durability, so let's have a little projection time.
In six full years, he's caught 128 games every year.
He's averaging 22 homers and 86 RBI's, with a slash line of 287/.359/.491. His OPS is .850, and OPS+ is 124.
Now, he's second in WAR for catchers since 2006, behind Joe Mauer. He leads catchers in homers, RBI's, and doubles (quick note: Martinez is techinically first, but he's been DH during for the last three years for some of that time). He's average defensively, so that won't help or hurt his case.
Now, here's come the projections. McCann is about to enter a baseball player's prime. So let's say he stays healthy, and bump his numbers pre-injury in 2011, where he was having his best season, and on pace for a 30/90 year. So we'll put put it at 28/90, with a slash line of .290/.370/.500 for age 28-32 seasons (five years).
That would give him 140 homers, and 450 RBI's. So, for his career up to that point, 276 homers and 987 RBI's, with a pretty good slash line of .290/.365/.495
I think, if he gets 300 homers and 1200 RBI's to finish out his career, he gets in if he stays healthy and durable.