Amazon has declared July 11 to be Prime Day, but it’s already evident the savings will kick off even earlier this year, what marks Amazon’s third attempt at such an event.

The first Prime Day was held on July 15, 2015, as a way to mark Amazon’s 20th anniversary, and it proved to be such a success boosting sales and bringing in new Prime members that the company did it all again on July 12, 2016.

With an Amazon-Whole Foods deal in the works, though, online shoppers might have their eyes set on supermarket staples this July in place of electronics, which have notably been best-sellers for the internet giant in past Prime Days.

“It’s no secret that some of Prime Day’s best deals have been on Amazon products – Audible, Kindle or even Prime Memberships,” Maya Mikhailov, co-founder of GPShopper, told CNBC.

Yet, considering how this year Amazon is using Prime Day to introduce customers to the company’s newest grocery offerings, and with more than 85 million Prime members, traditional grocery retailers should be “very worried” this time around, Mikhailov said.

Kantar Retail’s Werle also said she’ll be watching next week to see how Amazon leverages the visibility of its private-label brands, especially in the fashion department.

“Amazon seriously hopes to conquer the fashion and apparel market,” a new report from One Click Retail writes. During the first 23 weeks of the year, for example, apparel sales amounted to $1.45 billion, a 15 percent increase year-over-year from 2016, the firm has found.

A representative from Amazon did not immediately respond to CNBC’s request for comment on these figures.

“Traditionally, clothing and fashion accessories have been complicated to purchase online,” One Click Retail said. “But now, Amazon’s latest move, Prime Wardrobe, lets shoppers try on clothes and return them for free. These kinds of innovations are precisely why the online retailer continues to gain loyalty among digital consumers.”

Big-box retailers Target and Wal-Mart, electronics retailers such as Best Buy, now grocery store chains like Kroger, Supervalu and Albertsons, and even specialty apparel retailers — many of which are already at risk of filing for bankruptcy — should be paying attention to Amazon’s Prime Day. The company’s so-called lightning deals only continue to reach more categories for consumption.

“I could see Amazon doing a lot more with its fashion lines,” Kantar Retail’s Werle said.

To be sure, Amazon still only boasts a mere 5 percent share of total retail sales, excluding food, across the country, according to data from the U.S. Census Bureau.

Amazon’s share of retail sales across the U.S. in key categories — sporting goods, clothing, personal care and electronics — will only continue to accelerate from here, MKM Partners’ Rob Sanderson wrote in a recent note to client.

With an Amazon-Whole Foods deal in the making, pressure is about to hit traditional grocers head-on, as an internet giant takes on the “high-frequency” fresh foods market, Sanderson added. “[P]ressures on traditional retailers will only get worse,” and Prime Day could be the perfect launching pad.

Amazon and Whole Foods, meanwhile, continue to control only a sliver of the grocery market.

Whole Foods claims a 1.2 percent stake of all U.S. food and grocery sales, according to estimates and analysis from GlobalData Retail, and Amazon has about a 0.2 percent share of that market.