Panetta told reporters at the Pentagon on Thursday that putting American boots on the ground in Syria is a possibility under consideration by DOD planners and their counterparts in the region.
The DOD chief did note that if the decision was made to send in U.S. forces, it would be strictly to provide security for American or international teams working to secure Syrian chemical weapon arsenals when Assad is deposed.
That said, American troops would not be put in harms way in Syria if U.S. military leaders determined the situation in a post-Assad Syria was a "hostile" environment, Panetta added.
"Is there a permissive atmosphere [in a post-Assad Syria], or is it a hostile atmosphere? And that'll tell you a lot," he added.
Panetta's comments come days after recent intelligence showed there was no "imminent threat" of the Assad regime using chemical weapons against rebel forces in the country.
"I'm unaware of any information that would suggest that the Syrians are planning the imminent use of chemical weapons or deployment of chemical weapons," Pentagon press secretary George Little told reporters on Tuesday.
While the threat of those weapons may have subsided, "the bigger challenge" of making sure those weapons don't find their way into the hands of groups like al Qaeda or other terrorist factions has been a top concern among DOD officials, Panetta said.
"I think the greater concern right now is, what steps does the international community take to make sure that ... there is a process and a procedure to ensure that we get our hands on securing those [weapons] sites?" he added.
U.S. military leaders have been in talks with regional partners such as Israel, Turkey and Lebanon to begin piecing together a plan to make sure those weapon sites are secure if Assad falls, Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey said during the Thursday briefing.
During a speech at the National Defense University last December, President Obama said the use of chemical weapons by the Assad government against rebel fighters "would be totally unacceptable" and trigger an immediate and overwhelming response by the United States.
"The world is watching," Obama said at the time, in a warning directly aimed at Assad. "If you make the tragic mistake of using these weapons, there will be consequences, and you will be held accountable."
Days later, Panetta reiterated the president's comments, adding that any use of chemical weapons against Syrians would constitute crossing a "red line" that would inevitably draw a swift U.S. response.
For over a year, Assad's forces have mercilessly targeted rebel strongholds in northern Syria and across the country throughout the conflict, zeroing in on rebel positions with attack helicopters, heavy artillery and fighter jets.
Despite such attacks, rebel forces have been able to battle back against government troops in Aleppo and elsewhere in the country, recently taking the fight to Assad's doorstep in Damascus.