The specter of deflation is haunting more than New England Patriots quarterback Tom Brady. The whole U.S. economy is now grappling with its effects.

As growth splutters, the world's largest economy is facing the real possibility of a spiral in prices. On Thursday, the Producer Price Index for Final Demand showed that prices fell by 0.4 percent in April compared to March, and by 1.3 percent versus last April. The readings according to the previous-used PPI data series, known as PPI for finished goods, looked even worse, with a monster 4.4 percent year-over-year drop.

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Steep price drops can be perilous for the growth of an economy that's comprised of nearly 2/3 consumer spending. While falling prices may sounds attractive from a consumer standpoint, they are bad for the overall economy since deflation encourages people to save, rather than spend, money. After all, why spend a dollar today when it will be worth the equivalent of $1.05 tomorrow?

However—and perhaps unlike the Patriots' embattled quarterback—the U.S. has a good excuse for the potential deflationary shock: Oil.

Crude's slide over the past year has reduced macro price metrics tremendously. And indeed, when energy and food prices are stripped out to produce what's known as the "core inflation" measure, PPI for Finished Goods actually rose by 2 percent over the course of the year. On the other hand, the core PPI for Final Demand number still fell 0.2 percent from March to April.

Simultaneously, some maintain that no matter how noisy the inflation reading may be, there are still bad signs embedded in it.

"The PPI came in well below expectations and trying to pin the drop in wholesale prices on any one component would be a mistake," wrote Steven Ricchiuto, Mizuho's unconventional chief economist. "The loss of upside momentum in prices is broad-based."

For Ricchiuto, the number also points to a headache for the Federal Reserve in its quest to raise short-term rates. The central bank has set an inflation target of 2 percent, and no matter what the actual inflation number is, 2 percent does appear to be elusive at this point.

This despite years of ultra-loose monetary policy, which theoretically should spur inflation by making it more attractive to spend rather than save money. If inflation does not pick up, the Fed may not see fit to raise rates.

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"The PPI fits with my later-rather-than-sooner Fed call, and further supports my call for a sustained trading range on 10-year notes," Ricchiuto wrote.

That is, a delay in the Fed's rate-hiking plans would mean that Treasury bonds can stay put, instead of trading much lower as yields rise.

The key event for inflation-watchers will come on Friday, when April Consumer Price Index data is released. Economists are looking for inflation of just 0.1 percent, and 0.2 percent ex- food and energy.

But those more bullish than Ricchiuto, such as RBC senior economic Jacob Oubina, say that the April inflation reading should mark the "bottom" for inflation, with core inflation "grinding up" to 2 percent by year-end.

Oubina says that shelter makes up 42 percent of CPI, and since rental real estate "will continue to be in high demand, that alone will support the inflation backdrop as we make our way through the balance of 2015."

PPI is often used to forecast CPI, given that those produced goods will, in theory, be sold to consumers in the future. Yet the weak April reading doesn't spook the RBC economist, largely because it is such a "frustratingly volatile" economic reading.

"Energy and trade services alone pulled this index down. So the pass-through argument just doesn't pass the smell test," he said.

—By CNBC's Alex Rosenberg.

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