After going undrafted in the
2015 NBA draft, Roberts joined the
Washington Wizards for the
2015 NBA Summer League, where he recorded five rebounds in three games. He later signed with the Wizards for training camp on September 25, but was waived by the team on October 24 after appearing in three preseason games. On March 7, 2016, Roberts signed with the Brisbane Spartans for the 2016
SEABL season. After going scoreless in the team's season opener against the
Geelong Supercats on April 1, he scored 12 points the following day in a 91–65 loss to the
Kilsyth Cobras. He left the team in June 2016 in order to re-join the Washington Wizards for the
2016 NBA Summer League. In 13 games for the Spartans, Roberts averaged 8.5 points, 6.0 rebounds and 1.0 blocks per game. On September 23, 2016, Roberts signed with the
Milwaukee Bucks, but was waived on October 22 after appearing in five preseason games. On October 30, he was selected by the
Santa Cruz Warriors with the second overall pick in the 2016 NBA Development League Draft and in six games, he averaged 2.8 points and 1.2 rebounds in 7.3 minutes. On December 14, Roberts was traded, along the player rights for
Mac Koshwal, to the
Salt Lake City Stars in exchange for a second-round draft pick. In March 2018, Roberts signed with San Carlos of the Dominican Torneo de Baloncesto Superior (TBS), making his debut on March 27 in an 81–96 loss to Mauricio Baez. On May 8, he signed with
Pelita Jaya Energi Mega Persada of the
Indonesian League. Galloway arrived at the Mexican club
Soles de Mexicali in January 2019 and played three games with them in the
2019 FIBA Americas League group stage. In February, it was announced he had signed with another Mexican club,
Mantarrayas de La Paz, an expansion team going into their debut season in the
Circuito de Baloncesto de la Costa del Pacífico (CIBACOPA). ==References==