Yeah, that could work.
Then Jeffers or Caratini get dinged up in in game 1 of the playoffs and Banuelos has to fill in.
If playoffs were out of the picture, it's a no brainer. And it really hasn't been a concern carrying 3 catchers until Buxton is back. Twins always had the gaping Roden hole to fill so if they wanted a minor leaguer up, keeping 3 catchers doesn't hurt.
Honestly, I would maybe send Martin down for a bit in that scenario now. You would want Jenkins, Larnach and Buxton to get plenty of OF time plus you would still have Keaschall and Clemens (and Kriedler). If you wanted Sabato over Jenkins, you still have plenty of OF of you sent Martin down. He has been struggling (until Monday), so it might actually help him and he could come right back up Sep 1.