Tlass was the head of Brigade 105 of the Republican Guard in charge of protecting the capital Damascus.
The general's defection would have been "more powerful defection of his brigade defected with him," said Balout.
Without those troops, however, the defection does not pose a threat to Assad.
"Manaf was under home arrest for almost two years and he is not part of the security leaders in charge of the crackdown on the syrian uprising," said Balout.
Faysel Jaloul, an expert on Syria and researcher who is based in Paris, said the defection "no doubt is a symbolic and media victory for the opposition." When Assad's father died in 2000, the Tlass family remained loyal to the Assad family and Manaf Tlass helped engineer Bashir Assad's succession.
His defection will have little impact on the events in Syria, said Jaloul. After Bashar Assad became president, the Tlass family was sidelined and is not as influential as it was during the regime of the elder Assad.
Last month a Syrian Air Force pilot defected, flying his MiG21 to Jordan, which also was seen as a possible crack in the elite ranks of the regime.
Thousands of soldiers have defected to the rebels.
The Syrian uprising has reportedly cost 14,000 lives so far.
Intellpuke: You can read this article by ABC World News correspondent Nasser Atta, reporting from Jerusalem, in context here: abcnews.go.com/International/syrian-general-defection-symbolic-victory-weaken-regime/story?id=16725343#.T_c0iJHh7No