Injury/time out

[TriggerMN]

Team A is in control and head coach A asks for and is granted a time-out by trail official. Official asks coach whether he wants a full or 30, and the coach points to a player on the ground cramping up that neither official saw, and says, "We have an injury here."

Would you rescind the time out and have an official time out for the injury, or would you tell the coach that the time out has already been granted, so he's stuck with taking it?