During the first half of the match, a warning indicates that a planned half-time substitution could not be performed.
Possible causes and solutions
The player became injured during the first half:
The first half is calculated in full at kick-off. If the player selected for the substitution gets injured during the first half, they will no longer be available at half-time and the planned substitution cannot be performed.The player received a red card during the first half:
If the selected player is sent off, they will no longer be available for the planned half-time substitution.
Note
The first half is calculated at kick-off based on the team settings at that moment. Half-time changes are then taken into account when the second half is calculated.
Therefore, injuries or red cards that occur during the first half cannot be prevented or changed by a planned half-time substitution.