Arthur was selected by the New Orleans Hornets as the 27th overall pick in the 2008 NBA draft but was promptly traded to the Portland Trail Blazers for cash.

The Trail Blazers then traded Arthur to the Houston Rockets for draft rights to 25th overall pick Nicolas Batum.

[6] On September 3, 2008, Arthur and fellow former Kansas Jayhawks teammate Mario Chalmers were excused from NBA's Rookie Training Camp following a marijuana-related incident.

Fellow NBA rookie Michael Beasley was also reported to have been in the room at the time, but was not asked to leave camp.

[13] On June 27, 2013, Arthur was traded to the Denver Nuggets along with 55th overall draft pick Joffrey Lauvergne in exchange for Kosta Koufos.

[19] Seven days later, Arthur was traded to the Phoenix Suns in exchange for Jared Dudley and a 2021 second round draft pick.