Now, that's silly.
I'm reading all sorts of ridiculous excuses to rush a guy up, when he has a snowball's chance in hell right now. "Frustration" means exactly jack and shit when you're walking the yard, and forcing more workload on less-talented team mates in the bullpen. If he were to be rushed up now, WE'D all be frustrated, his team mates would be struggling [particularly the flimsy bullpen], and HE'D have the new excuse of having "lost confidence."
Here's a novel concept that many are reluctant to embrace: Let him EARN HIS SPOT by right of superior performance, instead of rushing him up Carson Fulmer-style. [And squandering an option year, and wasting his pre-arb controllable years while he figures it out, Carson Fulmer-style.]
Setting expectations for young men has never hurt anyone, and I'm still dubious about "frustration" harming his prospective MLB career, or hurting him in any way. Of course he's human, but I'm pretty sure he puts on his "big boy pants," irrespective of his emotions.
He's plenty young enough, and I'm willing to wait to try to find out if it were in any way possible to do. If a reduction in walk rate to 4-ish "cost him" a marginal declination in K/9 down to, say ~10ish, it would be worth it, IMHO. At the same time, his LD% suggests he'd be hit around were he to come up as well. I'd prefer that number to be south of 20%, as BABIP on line drives is high.
As an aside, there's something about the younger SPs in the org that I've wondered about. Consider the BB/9 for the following:
Rodon: 4.02 in 2017
Lopez: 3.96 this year
Fulmer: 6.68 in Chicago this year
Kopech: 6.06 in Charlotte this year
I wonder if this org would be better-served to focus on FB command/control for their higher-level SP prospects BEFORE having them master a change. [I don't know this to be the case or not, but the cavalcade of walks is irritating, and leads me to speculate about this.] Heck, even Lopez and Rodon, who are the best of the bunch, aren't exactly Mark Buehrle in terms of limiting the free pass.
Happily, Hansen's BB/9 was < 4.0 in all stops last year, so I'll concede that I may be finding trends where perhaps there aren't any. I just hate walks.