If the reports are correct, it's not known why Assad would do that, since he's blamed al-Qaida for suicide bombings against his embattled regime as a popular uprising moves into its 11th month.
It may be a message to the West, warning the Americans, British and French in particular they face retaliation if they provide the rebels with military support.
It could also be a gesture toward the Muslim Brotherhood, the most organized of Syria's opposition groups.
But if Nasr's on the loose again, trouble is likely on the way.
The influential al-Qaida icon, better known by his nom de guerre of Abu Musab al-Suri, has a $5 million U.S. bounty on his head. He allegedly inspired the July 7, 2005, triple suicide bombing of London's transit system in which four British-born jihadists killed 52 people and wounded more than 700.
Nasr, who trained as a mechanical engineer, is also wanted in Spain in connection with the March 11, 2004, bomb blitz that hit four commuter trains in Madrid, killing 191 people.
In 2003, he was indicted by a Spanish judge for building sleeper terrorist cells in the country. He's also been linked to a Spanish cell that helped the 9/11 hijackers prepare for the carnage in the United States.
The Syrian-born Nasr, who is married to a Spanish woman and holds dual Syrian and Spanish nationality, was arrested Oct. 31, 2005, by Pakistani police after a gun battle in the southwestern city of Quetta. He was handed over to the CIA several months later.
Nasr vanished into the legal limbo of the CIA's secret renditions and its global network of secret prisons and became a "ghost prisoner." There were reports he was in Afghanistan, Syria and India, although there was no confirmation of his whereabouts.
It seems the Americans quietly passed Nasr on to Syrian intelligence.
This may have been done in hopes of gaining access, through Syrian torture, to his intimate knowledge of al-Qaida's inner workings or perhaps in exchange for favors from Damascus, which has played hot and cold with al-Qaida over the years.
Unconfirmed reports said that after he fell into Syrian hands, Nasr was held in the top security prison in Aleppo, the city of his birth.
In August 2011, the Shumoukh al-Islam online forum posted a note that indicated Nasr was then being held in the headquarters of Syrian General Intelligence in the Kfar Sousa district of Damascus, a high-security zone where several of Syria's many intelligence services have offices.
In December, Sooryoon.net, a Syrian opposition Web site, claimed he'd been released.
Nasr was involved in the Muslim Brotherhood's war against Assad's father, Hafez, during the 1980s.
He fled Syria after the regime smashed the Sunni fundamentalists in February 1982, razing much of the city of Hama and slaughtering up to 30,000 people.
There has been no confirmation from Syria that Nasr has been freed. His whereabouts are unknown. It's unlikely, however, that he's still in Syria.
What makes him so important is his writings as Abu Musab al-Suri.
His masterwork, an encyclopedic, 1,600-page volume entitled "The Call for Global Islamic Resistance" has become the blueprint for jihad and draws heavily on the lessons of past conflicts.
"Al-Suri is emblematic of the rise of a new generation of jihadist strategic study writers, who are still a tiny minority but whose writings are informed by pragmatism, presented in a rational-secular style and emphasize a willingness to put political effectiveness before religious dogmas," the Jamestown Foundation, a Washington think tank, wrote in 2007.
Nasr had long advocated the decentralization of al-Qaida, which is how the jihadist movement has emerged since 9/11.
He didn't rate Osama bin Laden very highly and opposed his 9/11 terrorist spectacular, arguing it would trigger massive retaliation that would cripple the jihadist network, which is what happened.
Before his capture, he produced a series of lengthy tracts on jihadist ideology, training and objectives, particularly locally organized operations.
Western counter-terrorism officials say these treatises were a template for major al-Qaida attacks in Casablanca in 2003, Madrid in 2004 and London in 2005.
Notable deaths of 2014 [PHOTOS]