Economist Mohamed El-Erian said Monday he puts the risk of a recession in the United States at 25 percent to 30 percent.
"The road we're on is going to end. We cannot rely on central banks, and central banks cannot be the only game in town when it comes to policy," the former Pimco co-CEO said in a CNBC "Squawk Box" interview. "By 2017, we're going to tip only way or the other."
El-Erian said the American economy will continue to heal on its own, but growth troubles in other parts of the world, such as China, are holding back the U.S. He pegs domestic growth at 2 percent to 2.5 percent.
The chief economic advisor to Germany's Allianz, parent of Pimco, also said investors should get ready for more stock market volatility in the months ahead as the Federal Reserve and world central banks move in opposite directions.
"People forget how exposed we are to financial instability in the rest of the world," said El-Erian, pointing to the August spike in the CBOE Volatility Index, known as the fear gauge, as the stock market sank to its lowest levels of the year.
As the Fed appears ready to tighten, the European Central Bank and China's central bank continue on a path of easy monetary policies.
Late last month, the People's Bank of China cut interest rates for the sixth time since last November, and the ECB signaled it would consider extending its massive bond-buying program well into 2016 and even beyond.
"I don't think you can roll forward 'the new normal' for the next five years," said El-Erian, referring to the environment in 2009 of low economic growth, high unemployment and government debt problems.
In a CNBC interview last Wednesday El-Erian used a traffic light analogy to explain what he believes the Fed was trying to signal in its policy statement following its two-day meeting. He said lthe U.S. situation and international factors were flashing "yellow" and the Fed wanted to keep December "live."
There was no interest rate change at the October gathering, but policymakers left the door open for the first rate hike in nine years at their final meeting of the year, set for the middle of next month.
El-Erian told CNBC on Monday that he's becoming more concerned about the fallout of unconventional monetary policies, and the Fed and other central banks need their governments to step up on the fiscal side.
The stock market entered historically bullish November on Monday, after traditionally bearish October turned in the best month for Wall Street in four years.
Ahead of the government's October jobs report released on Friday, many Fed officials are scheduled to speak this week.