Perhaps I'm tired of trying to figure out what he could be. I watch a guy who struggles at positional play and technique around his own net, someone mesmerized by the puck who regularly chains together the wrong play when defending to wind up out of position and losing confrontations. It got worse as the year went on - maybe it was the concussion - but I don't see the bones of a good defender there right now outside of his handedness.
If they were to only acquire a single defender and it's someone to plug into the top 4, I can see retaining Jokiharju and having him at reduced time/role for when injury inevitably happens above him in the pecking order. I would rather they get what they had from him as a short-term, injury replacement #4 than a full-time #4.
If they acquire TWO defensemen, one of whom is that top 4 guy and another who is a capable #5 (in my caffeine addled brain, Zadorov) THAT guy would then be the temp at #4 and there is less need to keep Jokiharju at all.
If he can fix his positional play, improve his stick techniques, improve his d-zone gap and positioning, and his reads... he's still kind of undersized and not particularly dynamic. So... I'm more in favor of finding two guys and parting ways than just keeping him around in a shrunken role, hoping he might somehow fix his game. Maybe it's also that I'm really sour on Wolford's body of work thus far too to not think they have the guy on staff who can iron some of that out with him. Honestly, with the work Weber did in regards to things like those issues with guys like Pilut, Davies, and others on the AHL roster, maybe if he'd stayed I'd be more hopeful. And maybe Joker needs a more structured team system since it seems he's having post-concussion processing lag in all three zones, so that he can think even less and just react. I'm not sure. It would be herculean to fix the myriad issues he had to end last year. I don't see it as a single thread to unravel his fall, but a series of separate issues that all needed to be markedly better to get a guy who isn't a liability.