My thoughts exactly. Best case, you get a Todd Gurley - an all-pro caliber player ready late in year 1. Most likely, you get a Willis Macgahee - sit out a full year to rehab but get a very good player for a long time. Worst case, it's Javon Walker - struggles to ever regain the athleticism he had before the injury (sorry, was struggling for an example of blown out knee ruining a promising career).
Problem is, if the medical reports are good, Smith goes much higher and the Packers never have a chance. If the medical reports aren't good, he drops to the Packers who then have to decide if it's worth the risk. Packers haven't taken a medical risk in the early rounds since Harrell, so will be interesting.