De Kock was ruled out of the Tests and limited overs matches of the West Indian tour after tearing ankle ligaments during the first Test at Centurion, which South Africa won by an innings and 220 runs on Saturday.
Rossouw, 25, made his one-day international debut earlier this year and has been a prolific scorer for the Knights franchise and South Africa A.
He hit 231 for South Africa A against Australia A in Townsville in August, sharing a partnership of 343 with Temba Bavuma (162), who is also in the Test squad.
Bavuma was on the field throughout both West Indian innings in Centurion following De Kock’s injury.
The selection of Rossouw means that AB de Villiers, who took over as wicketkeeper in Centurion, will keep the gloves for the remaining Tests, starting in Port Elizabeth on December 26 and Cape Town on January 2.
Meanwhile, Windward Islands left-arm seamer Kenroy Peters will replace fast bowler Kemar Roach in the West Indies squad.
Roach suffered an ankle injury while bowling in the first Test. Peters, 32, was the leading wicket-taker in the West Indian domestic four-day competition in 2013/14.
Peters will be the second replacement in the touring squad. It was announced on Saturday that Narsingh Deonarine will replace injured batsman Assad Fudadin- AFP