Bassam bin Abdullah al-Sayrafi says: I asked Abu Ja'far (may Allah have mercy on him) about nardashir, and he disliked it and said that Ali bin al-Husayn (may Allah have mercy on him) used to play shaharadah with his family.
Imam al-Shafi'i (may Allah have mercy on him) says: If it makes him heedless to the point that the time of prayer passes, his testimony will be rejected because of his belittling the prayer.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الشهادات / 20971