The Houston Texans have signed rookie linebacker Isaiah Greenhouse off their practice squad.

To make room for Greenhouse, 2010 sixth-round guard Shelley Smith has been waived.

When the Texans take on the Oakland Raiders this afternoon, they'll be without linebacker Kevin Bentley, who is "Out" with a knee injury. 2010 fourth-round linebacker Darryl Sharpton (ankle) is "Questionable", and linebackers Xavier Adibi (hamstring) and DeMeco Ryans (quadricep) are "Probable".

Greenhouse, an undrafted rookie from Northwestern State, tied for the Texans' team lead with three special teams tackles during the pre-season.