Asim bin Kulayb (may Allah have mercy on him) narrates from his father (may Allah have mercy on him) that when the Prophet (peace and blessings be upon him) prostrated, his knees would already have rested on the ground before his hands.
Affan said: This hadith is gharib (strange). This hadith is counted among the solitary reports of Sharik al-Qadi; Hammam corroborated him through this route only as mursal (without the Companion). This is how al-Bukhari and other early hadith masters (may Allah have mercy on them) mentioned it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2630