Is the friend's statement "He who commits zina does not pray" considered a slander that necessitates the Hadd punishment, taking into account that the player has repeatedly been involved in sexual cases? And what should one do if it is indeed a slander? And is one sinful for slandering another person as a form of insult without their knowledge?

The implementation of the Hadd (prescribed punishment) for slander requires the request of the slandered person, and that the slandered person be chaste. If the Hadd is dropped, the Ta'zir (discretionary punishment) is not dropped if the slandered person is not a chaste, free, adult Muslim. The slanderer must repent to Allah by ceasing the sin, feeling remorse, and resolving not to return to it. It is sufficient for him to deny himself before those who heard the slander if the slandered person was unaware of it.