What happens when a player is available for selection for one team, but plays for the other team in a match?

In this case, the player in question will not get any points for the match. Here's how the fantasy points work for player transfers:

During the transfers from one team to the other, some players still remain available for selection in the previous team. This happens until the next scheduled team update is available. In such a case, you will not get any points for that player for the match.