The Washington Post is reporting WR DeSean Jackson , while being covered by cornerback Darrelle Revis in a joint practice with the Patriots, "made a cut to the inside but suddenly started hopping on his right foot and made his way to the sideline unable to put pressure on his left foot." It seems to be a left ankle/foot injury which was wrapped and iced while Jackson missed the rest of practice. The injury doesn't appear to be significant, but he is expected to miss the Redskins' first preseason game.
We'll update with more information as it's released. As long as the injury is not significant, Jackson can be viewed as a solid WR2 option with upside under new pass-heavy head coach Jay Gruden. He will surely blow the top of opposing defenses with his lightning speed and agile frame.