Cleveland Browns running back Trent Richardson, the third overall pick and projected centerpiece of the offense, could miss the preseason opener with a sore left knee.

There's no reason to worry right now. This could be precautionary. This could be an injury that goes away after a couple of days of rest. This really could be no big deal.

But there is reason to worry if this becomes a trend. The fact that this is the same knee that underwent arthroscopic surgery Feb. 3 has to cause some uneasiness for the Dawg Pound. And the fact that Richardson declined to talk to reporters about the knee doesn't clear up anything about the severity of the injury.

“We’re evaluating it,” coach Pat Shurmur told reporters, via WKNR in Cleveland. “There’s a chance he won’t play on Friday. I’m always concerned about injuries, but at this point we’ll just find out what it is. He’s been practicing well. Just a little sore.”

There's really no reason to play Richardson on Friday and put the knee at further risk. The Browns' focus has to be to get Richardson ready for the regular-season opener and not the preseason one. Richardson has had some issues getting on the practice field recently. He was removed from Saturday's practice with a headache before sitting out Tuesday with the sore knee.

At this point, it's wait-and-see mode for the Browns.