Foster has been struggling with niggles all season, but his latest problem may require surgery.
Rapoport wrote on Twitter: "Texans RB Arian Foster is out for the season, per sources. Multiple opinions revealed he needs back surgery.
"The #Texans will announce the move to put Arian Foster on Injured Reserve on Monday. It is a lumbar issue."
The Texans are yet to confirm the news, but they had already revealed that Foster would definitely miss Sunday's game with the Arizona Cardinals.