According to a recent practice report from NewsOK, Steven Adams was held out of practice on Thursday due to some minor back soreness. The Thunder insist that it's "nothing serious", and refuse to declare Adams day-to-day. It is the first official injury of this year's Thunder training camp.
Steven Adams has only missed significant time once in his two year career. That injury was a fractured right finger, which kept Adams out from February 9th to March 8th of this year. As far as we know, Adams has had no previous issues with his back.