James Bullard, president of the Federal Reserve Bank of St. Louis, is willing to reduce the central bank's bond-buying program in "small increments."

As the economy improves, Bullard is in favor of altering the pace of quantitative easing.

"You could adjust [QE] up or down" he added. "But the economy will most likely continue to improve and we'll be in a position to slowly ratchet down the pace of purchases." Bullard added that first-quarter economic growth looks like it's going to be "quite a bit stronger than we expected at the beginning of January."