Redskins WR DeSean Jackson injured his shoulder doing what exactly?

Injuries happen in training camp, but this is not how they're supposed to happen.

Washington Redskins wide receiver DeSean Jackson separated his shoulder, per ESPN, and could miss a few weeks. That's the "what" — now about the "how" ...

Pro Football Talk says Jackson suffered the injury by hitting a blocking sled. No joke.

(My follow-up question: On purpose?)

The 178-pound Jackson is one of the most electric NFL players, and he recently did say (via ESPN.com) that "no one can stop me." No one man, perhaps, but the sled might have won this battle.

This injury came in a joint practice with the Houston Texans, and HBO's "Hard Knocks" cameras might have witnessed the event, so already we've got two big injuries suffered under the show's watchful eye, along with Arian Foster.

What another weird story for the Redskins, who clearly don't need this with Robert Griffin III trying to rev his career back up, as he told Yahoo's Charles Robinson.