On 23 September 2014, Papanikolaou signed with the Houston Rockets. On 13 February 2015, he took part in the Rising Stars Challenge of the NBA All-Star Game; in spite of an injury-plagued rookie season, during which he averaged 4.2 points and 2.7 rebounds per game, while coming off the bench, the Rockets decided to pick up his team option for the 2015–16 season.