The 44-year-old was handed the interim head coach's role last June following Graham Ford's exit and considered a contender for the permanent position before returning to his fielding role once Hathurusingha arrived.
"After two incredible years with Sri Lanka cricket, this is the right time for me to move on to other opportunities, which will allow me to spend quality time with my young family," Pothas said in a statement issued by Sri Lanka Cricket.
"It has been an honour and a privilege to be involved with Sri Lanka. It has given me the opportunity to learn and improve as a coach as well as to contribute to a very talented bunch of players. It will always hold a special place in my heart."
(Reporting by Amlan Chakraborty in New Delhi; Editing by John O'Brien)
