Houston Texans coach Bill O'Brien has backed rookie Jadeveon Clowney as he continues to struggle with injury problems in his first year in the league.

Clowney has played in just four games so far this season and he has recorded just seven tackles and zero sacks as he struggles with a lingering knee injury.

"I do want to say that this guy has worked extremely hard to recover from injuries," O'Brien said, according to the Houston Chronicle.

"And I want to be real clear with this [about] him, as it relates to us here, to the Houston Texans: We think very highly of him. We know that he's going to be a really good player. And he's been unlucky."

O'Brien added that the number one overall Draft pick is day-to-day and he could miss this Sunday's clash with the Jacksonville Jaguars.