Spring football practice has already begun, at least for David Cutcliffe's Duke Blue Devils, so why not unveil ESPN's preseason Football Power Index (FPI) for the 2017 season? Anything to make the offseason go by a little faster. The FPI rankings may change some before the start of the season, but they're a starting point. We'll look a little closer today at three teams that might be overvalued in the preseason FPI and three teams that might be a little undervalued. OVERVALUED 3. Oklahoma Sooners Getting star quarterback Baker Mayfield back for another season was a huge coup for the Sooners, who finished last season on a 10-game winning streak. Mayfield's playmaking ability will give Oklahoma a shot in every game, but No. 3 seems a bit high for a couple of different reasons. The schedule, which includes a trip to Ohio State in Week 2, is challenging. Gone are running backs Joe Mixon and Samaje Perine and receiver ...