For argument's sake, let's say the numbers I posted are good predictors of what is to come (not true, of course), but for those who want Swihart to catch, instead of Vaz or Leon, think about this:
Swihart may get up to bat 3-5 times a game. Let's assume he will out hit both of the other catchers by 200 OPS points (.800 to.600 or whatever). That's just 3-5 PAs with a ,200 better OPS.
Now, think of a starting pitcher, who is usually involved in 18-24 PAs a game vs the opponents. See where I'm going with this?
Is it more important to have Swihart hit 200 points better for 3-5 PAs per game or to have our pitchers hold our opponents to 50-200 points lower over 18-24 PAs? I don't think anyone needs to be a math major to figure this one out.
Porcello: Nobody else has caught him. I don't want to mess with that.
Leon.
Sale: Swihart has not caught him all year. Sale does better 75 points better with Leon. I'd go with Leon here, but would be okay with Vaz- NOT Swihart.
Leon (Vaz OK)
Price: Leon does 182 points better with Leon. Swihart has not caught him this year.
Leon in a landslide.
ERod: He has been almost totally caught by Vaz, and while Leon did much better over just 43 PAs, I'm fine with sticking with Vaz, especially after last night's game. Certainly, I would not start using Swihart with ERod at this point in the season.
Leon or Vaz
So, with our best 4 starters, there's no way Swihart should ever start.
Let's go further...
Johnson: He has been caught pretty evenly by all catchers. He's the first one where CERA can really be used most effectively due to the sample size comps. Leon is 48 points better than Swihart and 160 points better than Vaz.
Leon is the clear choice here, too.
Velazquez: He has pretty even sample sizes, too. Vaz is just 23 points better than Leon, but he is 80 points better than Swihart.
Vaz or Leon.
Eovaldi: He has only been caught by Leon. He's struggled lately, so maybe a switch in catcher could work.
Leon or anyone?
Now, once the starter is removed, it looks to be okay to PH for a catcher (or two) as our RP'ers seem to be scattered on who they do better with. It makes more sense to bring Swihart in later in a game than to start him at catcher.
Kimbrel is pretty even with all (Swihart sample size is too small)
Barnes does better with Vaz and way better tahn Swihart.
Hembree does better with Leon, then Swihart.
Brasier has never been caught by Vaz.
Workman does way worse with Leon.
Thornburg way better with Leon.
Pom does way better with Swihart.
I can't help but think it would be absurd to think Swihart should be our starting catcher, and some want to boot Vaz or Leon out by next year. A 200 point gain on offense, which is certainly not a given, since his OPS is .582 this year is NOT enough to offset the expected loss we'd have with our pitchers.