De Kock, 22, a free-scoring left-handed opening batsman and capable wicketkeeper, tore ligaments in his right ankle while warming up during the first Test against the West Indies on December 19.
It was estimated that he could be out of action for between 10 and 12 weeks, which would probably mean him missing at least South Africa’s first two World Cup matches, against Zimbabwe on February 15 and India on February 22.
De Kock has become such a valuable member of the one-day side, with six centuries in his first 35 one-day internationals, that the selectors are willing to gamble on him recovering in time to play the team’s later pool games and in the knock-out stages, with AB de Villiers taking the gloves in the interim.
World Cup regulations make provision for teams to name injured players and replace them before the tournament, or if they aggravate the injury at the tournament, provided a medical certificate is produced.
There are no major surprises in the squad, although there are two changes from the 15 that were beaten 4-1 in a series in Australia in November.
Left-handed batsman and off-spin bowler JP Duminy and left-arm spin bowler Aaron Phangiso return after missing the November tour because of injury.
All-rounder Ryan McLaren, the side’s leading wicket-taker in both 2013 and 2014, was dropped after a dramatic fall-off in form since suffering a broken arm against Australian fast bowler Mitchell Johnson in a Test match last season.
Robin Peterson, a veteran of three World Cups who replaced Phangiso in Australia, was also omitted.
South Africa’s challenge will be spearheaded by a strong batting line-up, in which De Villiers and Hashim Amla have outstanding records, while the powerful fast bowling trio of Dale Steyn, Morne Morkel and Vernon Philander will be complemented by leg-spinner Imran Tahir, who has taken 47 wickets in 27 one-day internationals.
De Villiers said he was confident the right squad had been chosen.
“It’s a huge honour. I’m very confident. We know we have to keep our feet on the ground and work hard. It’s a huge tournament which we have never won before and we want to bring it home.”
In contrast to previous South African teams, there is a shortage of top-quality all-rounders.
Duminy is likely to be a key player but batting all-rounder Farhaan Behardien and bowling all-rounder Wayne Parnell are not guaranteed places in the starting line-up.
The South Africa squad will play in a five-match one-day series against the West Indies, starting on January 16 with Morne van Wyk standing in as wicketkeeper in place of De Kock.
South Africa squad:
AB de Villiers (captain), Hashim Amla (vice-captain), Kyle Abbott, Farhaan Behardien, Quinton de Kock (wkt), JP Duminy, Faf du Plessis, Imran Tahir, David Miller, Morne Morkel, Wayne Parnell, Aaron Phangiso, Vernon Philander, Rilee Rossouw, Dale Steyn.
Head coach: Russell Domingo
Assistant coach: Adrian Birrell
Bowling coach: Allan Donald
Spin bowling coach: Claude Henderson