It's "almost a given" that the Federal Reserve will taper its quantitative easing (QE) this year, but that action won't come as a result of strong economic growth, says Pimco CEO Mohamed El-Erian.

The economy grew 1.7 percent in the second quarter, after a 1.1 percent expansion in the first quarter. That's not vigorous enough to justify a cutback in the Fed's $85 billion of monthly bond purchases, El-Erian tells CNBC.

"The reason they'd be doing it is because they're starting to get more and more worried about what [Fed Chairman Ben] Bernanke has called the 'cost and risk of prolonged unconventional and experimental monetary policy,'" he explains.

Editor's Note: I Wish I Were Wrong — Economist Laments Being Right. See Interview.

The Fed has been utilizing such policy since 2007, building up its balance sheet to $3.57 trillion.

To emphasize its sustained support for the economy, the Fed will keep trying to shift the market's focus from QE tapering to the central bank's continuation of near-zero short-term interest rates, El-Erian notes.

So far the stock market is eating it up, with indexes rising to record highs Thursday. Stock investors are "hearing the two things they want to hear, which is gradual economic improvement and central banks in business-as-usual mode," El-Erian asserts.

In the end, "I think the economy is improving and continues to heal," he argues.

Others too see the Fed tapering soon.

"They're reiterating their expectations that economic growth is going to pick up," Jeffrey Rosenberg, chief investment strategist for fixed income at BlackRock, told Bloomberg, referring to the Fed's statement after its policy meeting Wednesday.

"Clearly the Fed is trying to get out of the business of QE."

Editor's Note: I Wish I Were Wrong — Economist Laments Being Right. See Interview.