The guy already hit over .830 for a 2 year stretch of over 900 PAs.
I'd say he still has potential to hit in the high .700's again. He also hit .793 in his last 106 games last year.
To pretend this is the JBJ we will be stuck with, and that he has no more upside, is not what I call being realistic.
Can JBJ end up near .550 to .600 this year? Of course, he can, but my guess is he ends up over .700 again, which would mean he's have to hit hith .790s the rest of the year, and that would make him a plus going forward.
I could be wrong, but I'm not writing him off, yet.