"We don't know precisely what the military operation would look like," Little told reporters at the Pentagon, regarding the projected costs for limited strikes inside Syria.
Little's comments come hours after Chief of Naval Operations Adm. Jonathan Greenert suggested the Pentagon could be forced to seek supplemental funding to pay for U.S. operations in Syria.
"A supplemental [request] might be the order of the day, as we work through how long operations [may be] going on" in Syria, Greenert said during a speech in Washington on Thursday.
U.S. naval operations in the region could cost Washington upwards of $75 million per week, according to the four-star admiral's estimates.
That total is based on predicted operating costs for the five Navy destroyers and one carrier strike group that have been positioned near the Syrian coastline.
Those American warships have been on station in the Mediterranean for several weeks, awaiting White House orders to begin the strikes.
Earlier this year, Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey suggested to Congress that supplemental funding would be the only way the Pentagon could afford military action in Syria.
"We have conducted limited military operations in the past" and will do so, if necessary, to eliminate the threat of chemical weapons by forces loyal to Syrian President Bashar Assad, he said.
The strikes being considered by the White House are in retaliation to reported chemical strikes by Assad forces against anti-government rebels in the country.
Use of those weapons crossed a so-called "red line" with the administration, triggering plans for military action.
U.S. forces were poised to strike in late August, but President Obama delayed the attack in order to seek congressional support for any military action in Syria.
But the significant costs associated with action there, just as the Pentagon is facing a $500 billion budget cut under sequestration, has a number of lawmakers balking at the operation.
Oklahoma Sen. James Inhofe, the top Republican on the Senate Armed Services Committee, said the Defense Department is in no position, financially, to carry out military action in Syria.
"Our troops are stretched thin, the defense budget has been slashed to historic levels, and we are facing an unprecedented time of unrest across the Middle East," Inhofe said.
"No red line should have been drawn without the strategy and funding to support it," he added.
For his part, Little refused to comment on the fiscal planning measures being taken inside the Pentagon to pay for possible action in Syria.
"We will afford it if this moves forward ... [but] what we need to focus on is the objective" to eliminate Assad's chemical weapons capabilities, he said.