Dorsey was chosen as the 33rd overall pick in the 2008 NBA draft by the Portland Trail Blazers. After the draft, he was traded to the Houston Rockets in exchange for the draft rights to the 25th pick, Nicolas Batum. In the 2008–09 NBA season, Dorsey played in 3 games, scoring a total of 2 points, grabbing one rebound, and making one assist. The Rockets assigned Dorsey to the Rio Grande Valley Vipers of the NBA Development League. On February 5, 2010, after previously being called back up from the NBDL, Dorsey played a career-high 19 minutes and grabbed 12 rebounds.
On February 18, 2010, Dorsey was traded to the Sacramento Kings in a three team deal that also moved the Rockets' Tracy McGrady to the New York Knicks. On March 28, 2010, he was waived by the Kings. On April 4, 2010, Dorsey was signed to a non-guaranteed contract by the Raptors.
Europe
In September 2011, Dorsey signed a one-year deal with the Spanish League club Caja Laboral. On January 10, 2012, he parted ways with Caja Laboral. The next day, he signed with the Greek League club Olympiacos for the rest of the season. With Olympiacos, he won the 2011–12EuroLeague championship, as well as the 2011–12 Greek League championship. In August 2012, he re-signed with Olympiacos on a two-year deal. On September 12, 2012, during a preseason exhibition game against Dinamo Sassari, Dorsey ended up shattering a backboard, with around two minutes left in the fourth quarter. On November 7, 2012, Dorsey was released by Olympiacos, ending their relationship two weeks after he criticized the organization, and he stopped playing with the team. On November 22, 2012, he signed with Turkish club Royal Halı Gaziantep for the rest of the 2012–13 Turkish Basketball League season. On July 17, 2013, Dorsey signed a one-year deal with the Spanish club FC Barcelona.
Return to the NBA
On July 19, 2014, Dorsey signed with the Houston Rockets. On January 21, 2015, he had a season-best game with seven points and 12 rebounds in a loss to the Golden State Warriors. On July 20, 2015, the Rockets traded Dorsey, Nick Johnson, Kostas Papanikolaou, Pablo Prigioni, a 2016 first round draft pick, and cash considerations to the Denver Nuggets in exchange for Ty Lawson and a 2017 second round draft pick. On August 18, 2015, he was waived by the Nuggets in a buyout deal.
Return to Europe
On August 29, 2015, Dorsey signed a one-year, $650,000 net income contract with Turkish club Galatasaray. On February 19, 2016, he left Galatasaray, and returned to his former club, FC Barcelona, for the rest of the season. On August 17, 2016, Dorsey signed a two-year contract extension with Barcelona. On January 18, 2017, he was released from the team due to disciplinary reasons. On February 13, 2017, Dorsey signed with Turkish Super League club Best Balıkesir for the rest of the 2016–17 BSL season. On November 2, 2018, Dorsey returned to Greek Basket League after six years, penning a deal with Panionios B.C. until the end of the 2018-19 season. Dorsey made 20 appearances and averaged 9 points and 8.8 rebounds in 22 minutes per game, helping Panionios to get some crucial victories in order to avoid relegation. On November 29, 2019, he has signed with Syntainics MBC of the Basketball Bundesliga. Dorsey parted ways with the team on July 21, 2020.
