SANTA CLARA, Calif. – Prior to practice on Wednesday, San Francisco 49ers defensive lineman Justin Smith said he believed that inside linebacker Patrick Willis will "definitely" be back on the field Sunday against Houston.Later in the day, Willis made nice strides by practicing on a limited basis.Willis suffered a groin injury in a Week 3 loss to Indianapolis, and he missed the 49ers' game last Thursday at St. Louis. Willis said he is making progress and is hopeful he can play Sunday, as is coach Jim Harbaugh.