Ereck Flowers has spent the majority of his career as the butt of many jokes. Selected in the first round out of The U, Flowers was placed at left tackle by the New York Giants. His time there, was not ideal, getting beat almost from his first professional snap and throughout his career there.
New York moved him to the right side a few years later, but to no avail. Flowers had some of the worst protection numbers in the league, finally leading to his release. That's why it's so interesting that he seems to have found a home in Washington with the Redskins and at left guard.
Interior offensive linemen don't need the same level of athleticism as external tackles do. The interior guys are more in a phone booth, where strength and leverage win the day more often than not. It is in this vein the Washington coaching staff feels they may have stumbled onto something and provided themselves with another key piece to an offensive line that has been sporting a bit of a struggle face this offseason.