 Grella made his debut for New York on 8 March 2015 appearing as a starter in a 1–1 draw at Sporting Kansas City.On 28 March 2015, Grella scored his first goal for New York and the 1,000th goal in club history in a 2–1 victory over Columbus Crew.On 17 April 2015, Grella scored his second goal of the season for New York in a 2–0 victory over the San Jose Earthquakes.