The U.S. economy grew 3.9 percent in the third quarter, and many economists predict it will expand about 3 percent through next year.

But Bill Gross, the former Pimco founder who is now a fund manager at Janus Capital Management, thinks that's off base.

"Yes, we're starting from a 3-percent growth economy that will probably persist for another quarter or so," he told CNBC. "We get back to a relatively new structural growth rate, which is not 3 percent, but probably 2 percent or even less."

The plunge in oil prices to five-year lows will help spark the growth slowdown, as the energy industry suffers, he said.

Oil's decline also has helped push the dollar down, and that will affect financial markets, Gross said. "Financial markets try to readjust. Hedge funds reduce leverage and sell other positions."

Under these conditions, the Federal Reserve will be slow to increase interest rates, Gross said. "Why would the Fed raise interest rates to slow economic growth if in fact inflation was moving lower?"

Most economists expect the central bank to raise interest rates starting around mid-2015, and most believe the hikes will be small.

But former Fed Gov. Frederic Mishkin, now a professor at Columbia University's Business School, says the central bank must consider large rate increases once it moves. The Fed has kept its federal funds rate target at a record low of zero to 0.25 percent for six years.

Given the current low level of inflation, "my view is a sensible strategy for the Fed is to be patient, not to be trigger happy to raise rates," he told MarketWatch.

But the Fed must "recognize that does mean they may get to a point where they have to raise rates faster than they otherwise would."

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