Who was responsible for getting Sai Baba to leave for the Chavadi procession?

The person primarily responsible for initiating Sai Baba's departure for the Chavadi procession was Tatya Patil. As described in Chapter 37, Baba had a routine of waiting for Tatya to arrive, even if He was otherwise ready to go. Tatya would approach Baba, put his hand under Baba's arm, and only then would Baba stand up to begin the journey. This illustrates the deep and unique love between them, with Tatya even calling Baba 'Mama' (uncle). Without Tatya's arrival and specific action of helping Him up, the procession would not commence.