Desmond Oh's professional basketball career started in 2008 when he played a few games with the
Singapore Slingers while the team was competing in the 2008/09 Singapore Challenge Series. In August 2009, Oh signed a one-year contract to play for the
Singapore Slingers along with 7 other local players. As a raw young talent, his role consisted mainly of shutting down opposing team's guards. Then, he earned his nickname, "D-glove". On 1 September 2010, Oh was one of four local players brought back to play with the team from the previous season. Oh was given a bigger role in the second ABL season when local star
Hong Wei Jian went down with a career-ending injury during a local Division One basketball game. He averaged 3.6 points and a career best 0.89 steals that season. For the 2011-2012 Asean Basketball League season, Desmond, together with
Wong Wei Long and
Shengyu Lim, were the first trio of Singaporeans that renewed their contracts with the Slingers on 29 November 2011. He went on to average career-highs in minutes, points, rebounds, assists, three-point field goals and steals for the 2012 Asean Basketball League season. Oh's best game came on 18 January 2012 when he scored a career-high of 16 points against the Chang Thailand Slammers, a game that the Slingers went on to win. Oh was selected as a special ABL import with the
Westports Malaysia Dragons against a US Professional Basketball Alumni team, bannered by former NBA stars
Scottie Pippen,
Dennis Rodman, and
Mitch Richmond on 17 July 2012. On 10 December 2012, Oh re-signed with the Slingers for his fourth straight season for the 2013 Asean Basketball League season. ==ABL career statistics==