Here's my more balanced view on this...
Part of Devin's struggles are related to the way Ty is using him. The post-heavy structure of the starting lineup isn't well suited to his abilities. I understand the desire to put him out there, see how he adjusted, and hopefully keep his stock high.
But, at this point, there is a real chance his stock is as low as it can get. In other words, by simply waiting until the end of the season Harris's value might increase as an expiring contract. Once this becomes more-or-less the case, and the jazz aren't worried about the impressions of moving him to the second unit, I hope they do so -- and then institute more of an up-tempo PnR system that might actually revive him.