J.C. Penney's steep discounts are going to hurt the retail sector this holiday season, Durbin Captial Portfolio Manager Steve Kernkraut said Thursday.

"I would be very cautious about the retail sector going into the holiday season," he said, citing weak quarterly results from Limited Brands and Buckle, as well as back-to-school sales that were "disappointing."

On CNBC's "Fast Money," Kernkraut said foundering retailer J.C. Penney's efforts to lure back customers would involve severe price-cutting.

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"The holiday season is going to be horrific for the department stores, the apparel retailers, because Penney's is going to be selling everything 40-50 percent off to get some attention from the consumer. So, you really have to be somewhat of a fool to pay full price at some of the other retailers as a consumer."

Discounts of more than 40 percent are going to be likely in a shopping climate where such sales were now the norm, he added.

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Kernkraut said the retail sector was also facing challenges from the lack of consumers' attention, noting that they're spending on mobile devices, cars and houses.

"They're not buying apparel," he added. "They're not buying department store goods."

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Kernkraut, former president of J.C. Penney Credit Services and former vice president of credit at Macy's, said he likes Michael Kors and Under Armour.

"I think you really have to have a name brand that's differentiated, that's not a commodity product," he said. "When J.C. Penney sells their St. John's Bay polo shirt for $6.99, who's going to buy a Gap shirt? Who's going to buy [a] Target shirt? Who's going to buy a Sears shirt? But in terms of Michael Kors and Under Armour, consumers want to get it. They know the brand. They want to get it. Nike's another example of that."

— By CNBC's Bruno J. Navarro. Follow him on Twitter @Bruno_J_Navarro.