Houston Texans linebacker Jadeveon Clowney is still something of an enigma just six months into his NFL career.

Is he a talented, young professional doing his best to deal with an unfortunately nagging knee injury, or is he a rookie making excuses for his inability to get on the field, stay on the field and make the big plays for which he was drafted?

It is debatable which scenario is correct, but it all amounts to the same thing for the Texans - Clowney (he of the major draft status and unending hype) - has not been performing up to expectations thus far in his rookie season.

Part of that has been health-related, there is no question. He suffered a knee injury during Houston's season opener against the Washington Redskins and was forced to undergo arthroscopic knee surgery that kept him out of the lineup for several weeks.

"You never know if you're going to have an injury or not coming into the league. So when that happened to me, it was a setback," Clowney said, according to John McClain of The Houston Chronicle. "I'm just trying to do everything I need to do to get back to where I need to be to help the team out."

But since his return against the Tennessee Titans on Oct. 26, he hasn't performed anywhere near the manner in which the Texans and their fans hoped he would when they chose him first overall in May.

According to Clowney, something, possibly that injury, is keeping him from achieving the way he knows he can.

"Some things are holding me back still but I'm just out here trying to do what I can do and have fun," he said.

Clowney had only three tackles, one of which was for loss, and a poorly timed neutral-zone infraction that helped set up the Cincinnati Bengals for a field goal in his most extensive action of the year this past weekend, according to ESPN.

Afterwards, Clowney seemed to shrug off his seemingly mediocre stats as just part of the fickle nature of the game.

"Sometimes, I can only do my job, which is set the edge and get after the quarterback. Sometimes you get that and sometimes you don't."

Clowney has plenty of time left to write the story of his NFL career, but if he's going to go down as one of the best - which is what is generally expected of a first-overall pick - he's going to need to get healthy and get back to making the plays that turned him into such a highly touted prospect in the first place.