De Kock was preferred in the squad ahead of Ryan Rickelton, which Moroney says was a big decision for them to make.
Although he only recently returned to international cricket, the selectors felt that there’s no better person to have in big matches than the 33-year-old.
"If you got a batsman with that kind of experience and you're potentially playing in a World Cup final in front of 130 000 spectators, one of the guys you back to be in the middle is Quinton de Kock.
"He's been brilliant since he's been back, and I'm also getting fantastic feedback from his team in the SA20."
Tristan Stubbs is another notable absentee in the squad, with David Miller getting the nod ahead of him.
Moroney says the decision was more influenced by the way they want to set up in the middle order.
"What we have looked for is an attacking middle order, where the left-handed David Miller slots in for us, and then with Brevis and Ferreira complimenting him on either side is the plan we have gone for."
In terms of injuries, he says they haven’t really had any problems that have influenced selection.
Players like Kwena Maphaka and Kagiso Rabada did not take part in the recent T20 International series against India, and will have the whole SA20 to get match-sharp ahead of the tournament in India and Sri-Lanka.
Speaking of the SA20, Moroney says it hasn’t really played any role in the selection of the squad with only seven days of the tournament played thus far.