The Yoshida Issue may end up solving itself, if he does nothing over the next 1-3 weeks. It's hard to imagine the leash being longer than that, if he keeps doing little or nothing.
It would be one thing, if he was replacing players hitting in the 5 or 6 hundreds, but he's not, and I'm not just talking "hot hand," here. Some of these guys are hitting better than he is and better than his career .754 for this full season.
Of course, we have to realize some of the guys hitting better than him may be on unsustainable paths, and can come crashing down to earth, at any moment. If they do, even Yoshida at .600 to .650 might be an upgrade, but it's hard to project this to happen, right now. Valdez, DHam and Romy don't seem to be letting up. Ref and O'Neill are both hitting like they deserve a FT slot in the order. Abreu is back off the IL and absolutely kills RHPs.
If Yoshida could play 1B, we could play him there, until Casas returns, but he doesn't. Our OF is already squeezed with the Abreu return and Ref going nutty, again. Moving Rafaela to SS helps a bit, and squeezing Vadlez/DHam/Romy looks to be better than squeezing Duran/O'Neill/Abreu/Refsnyder. It looks like DH is the only place for him, but it had been a place to get Ref, O'Neill, Valdez and others some more playing time, and they have been rocking the joint.
To me, when healthy, these guys need to play almost exclusively FT:
Devers 3B
Wong C (as much as we can without burning out his legs)
Casas 1B
Duran LF (CF when Rafaela plays SS)
Rafaela CF/SS
O'Neill LF/RF/DH
Refsnyder DH/LF/CF
That's seven slots taken.
Abreu should start vs all RHPs, and Valdez & DHam have done well enough to keep playing vs RHPs, too, but Yoshida will get the look over them, if possible. Since Yoshida does not play 2B, he won't beat them out, there. Sadly, it will come down to benching an OF'er vs RHPs, so Yoshida can DH.
Oddly, Yoshida has a better situation to DH vs LHPs, due to the unbalanced nature of our batters, especially the OF. Since Abreu sucks vs LHPs, he's an easy platoon choice. Valdez has not earned the right to start vs LHPs, either, so DHam and Romy can play 2B or 2B & SS, as Rafaela plays CF (or SS.) We could play Rafaela at SS, Duran in CF, Refsnyder in LF and O'Neill in RF with Yoshida at DH.
It's too early for me to say we should DFA him, if nobody takes him off our hands at 10-20% of his cost, or even 5%. He could still find a groove and redeem himself, but at whose expense?