Sulayman al-Taymi (may Allah have mercy on him) said: I asked Tawus (may Allah have mercy on him) about a wounded man who intends to perform ablution or take a ritual bath for janabah while he has tied a bandage (over the wound). He said: If he fears (that harm will befall him), let him wipe over the cloth, and if he does not fear, let him wash it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1084