Watt got his arm tangled up with other players during a running play on Thursday, which supposedly led to the dislocated elbow. Trainers then popped his elbow back into place (ouch) from there, but Watt hasn't returned to practice since and isn't expected to return for a while. He'll likely even miss the preseason.
But if he feels like he'll be back in the opener, or even it's the second or third game, Texans fans can't be too worried about the injury. The overall tendency to deal with key injuries is still alarming, though.