Steenkamp scooped the award ahead of fellow Springboks Gio Aplon, Francois Hougaard, Schalk Burger and Juan de Jongh.
The latter pair, like Steenkamp, have been ruled out of the Springboks four-test tour that kicks off against Ireland at the Aviva Stadium on Saturday.
Steenkamp, capped 31 times, has not played since the Springboks' Tri-Nations loss to Australia in Bloemfontein in September, but picked up three tries in the six games he did play.
The prop was also instrumental in helping the Bulls to a third Super 14 title in four years.
Elton Jantjies, one of six uncapped players on the Boks' forthcoming tour, was named young player of the year ahead of Pat Lambie, whose man-of-the-match performance in the provincial Currie Cup final also earned him a Springbok call-up.