Vaishnava Samhita. Vitthalanatha Charitam. Vol III Book VII Chp 3 Shloka 1

श्रीसद्गुरुरुवाच 
श्रीवल्लभस्य तनयो गोस्वामी विड्ठलः स्मृतः |
यस्य कीर्तिपताकैवमद्याप्युच्चलति व्रजे ||

Shri Sadguru said

Shri Vallabha had a son named Vitthala Goswami. Till this day, his fame has been permeating the very air of the Gokulam.