Can a player play without a registration card?

No. SAFA Competitions Uniform Rule 11 applies "no card, no play" without exception.

• Every player must be properly registered before being named on a team sheet.
• Registration cards must be available for the referee to inspect one hour before the match. The referee checks every player's card in front of both teams' representatives and the players.
• Fielding a player without a valid card, or failing to produce the cards, is misconduct and the team forfeits any points earned in that match.
• "Fielding" includes naming a player as a substitute, even if they never come on.
• Giving false information when registering a player is an offence. The team must make sure the information is accurate: the issue of a card does not take that responsibility away.