Assad appointed his chief of staff, General Daoud Rajha, to replace Ali Habib as defense minister, the television said.
The position of defense minister is a mostly ceremonial post in Syria, with most officers from the minority Alawite sect, the same sect as Assad, dominating the majority Sunni rank-and-file army.
The military is effectively under the command of Assad's feared brother Maher. Assad's brother-in-law, Assef Shawkat, is also deputy chief of staff and diplomats say he plays a key role in the control over the army.
The European Union imposed sanctions on Habib this month as part of measures against Syria's ruling hierarchy for their bloody crackdown on five months of pro-democracy demonstrations.