The international keeper ruptured a leg muscle during a Serie A match against Palermo in early October, and has been kept on the fringes ever since.
The towering guardian was expected to make his comeback in the immediate future, but apparently he needs more time to fully recuperate.
"It's a little more serious than expected," Buffon was quoted by skysports.com as saying.
Initial examination indicated that the 30-year-old would only need a couple of months to reach full recovery, but the tear turned out to be more serious than previously thought.
"I still have to recover physically, but I should be ready for 2009," he said
During Buffon's ongoing lay-off, Austrian Alex Manninger has been deputizing for the world cup winner, and the latter believes the substitute guardian is doing great.
"The last few games have shown I'm not indispensable," added Buffon.