What is the evidence in the texts that connects Sai Baba to the worship of Lord Vitthal?

Chapter 4 illustrates a deep connection between Sai Baba and Lord Vitthal through multiple devotee experiences. Some devotees referred to Baba as the "living Lord of Pandhari." Baba himself promised Das Ganu that Vitthal would appear in Shirdi if the devotee was full of faith, stating one need not go far to see Him. This was proven when Kakasaheb Dixit had a vision of Vitthal that Baba confirmed, and when Bhagwantrao Kshirsagar was brought to Shirdi by Baba to resume the worship of his family's Vitthal idol, whom he had been neglecting. These accounts collectively portray Baba as being one with Vitthal, or at the very least, a powerful facilitator of Vitthal's grace.