The Italy international, who was at Parma when the offer was made, turned down the opportunity to move to Spain and instead opted to sign for Juventus.
Buffon told reporters: "I do ask myself what my career would have been like now and again.
"But Barcelona only started winning in 2006. Five years without winning anything is a long time.
"Seeing how my career has developed, I have no regrets."
The 34-year-old recently signed a new two-year contract to extend his stay at the Turin club.