One interesting note with Kimbrel is that he was absolutely spectacular when throwing to JT Realmuto (1.86 ERA, .535 OPSA) and absolutely awful when throwing to Garrett Stubbs (8.04 ERA, .838 OPSA).
He pitched 17 times with Stubbs behind the plate, so it’s not as though that was just one or two bad days inflating the numbers. Kimbrel had 5 outings where he gave up multiple ERs, and Stubbs was the catcher on 3 of those 5 occasions (60%). He gave up any runs at all in 16 outings, and Stubbs was the catcher on 7 of those 16 occasions (44%). That seems pretty noteworthy when you consider that Stubbs only caught him in 17 of his 71 outings (24%).
Stubbs really only started catching full-time (well, as a full-time backup) in 2022. He certainly does not have the background to match guys like Realmuto, Rutschman, and McCann. Perhaps Elias and his crew think there’s something to exploit in that data.