 On 7–8 March 2016, Messina again served as head coach of the Spurs, for two games, due to Gregg Popovich leaving the team for a family emergency.On 19 April 2018, Messina temporarily took over head coaching duties of the team in their playoff series versus the Golden State Warriors, due to Popovich having left the team in light of his wife's death the previous night.On 11 June 2019, Messina signed a three-year contract, and agreed to become the new head coach and President of Basketball Operations of the Italian club Olimpia Milano.