Free Syrian Army
A former Syrian Army General named Mustafa al-Sheikh said to Reuters that 20,000 soldiers defected since beginning of the war. And that the Free Syrian Army had taken control of a lot of land and later said in an interview "If we get 25,000 to 30,000 deserters mounting guerrilla warfare in small groups of six or seven it is enough to exhaust the army in a year to a year-and-a-half, even if they are armed only with rocket-propelled grenades and light weapons". Multiple defections happened in 2012.