Dick's Sporting Goods is declaring a war on prices to defend its market share and protect its private-label brands, the retailer said on Tuesday.

"We are intentionally joining the battle, and we will aggressively be promoting our business to drive market share to our stores and online," CEO Edward Stack said on Tuesday's earnings conference call.

Shares of Dick's were last sinking more than 21 percent on the retailer's weak profit outlook and stark warning about the health of the broader sporting goods industry.

Many of Dick's partners and its rivals were being dragged down with it. Hibbett Sports shares sank more than 10 percent. Shares of Under Armour, Foot Locker and Big 5 Sporting Goods were all falling around 4 percent. Cabela's was down 3 percent, Callaway Golf Company down 2 percent, and Nike down 1.8 percent.

"There's a lot of people right now ... in retail and in this industry in panic mode," Stack added. "They seem to be in panic mode with how they're pricing, and we think it's going to continue to be promotional, and at times irrational, going forward."

Stack said he noticed heavier promotions and price cuts particularly on athletic apparel, electronics, and hunting, fishing and camping gear beginning around Father's Day this year. "And it continued to be very promotional — not only from retailers but also from some of the brands on a direct-to-consumer basis."

Dick's has since launched a "best price guarantee," where it promises customers that if they find a lower price on a product, Dick's will match it.

Another concern for Dick's and its peers has been Amazon's latest encroachment on the industry. The internet giant recently inked a partnership with Nike to sell its merchandise on Amazon.com, threatening any company without a strong e-commerce presence.

"We'll see how this goes," Dick's CEO Stack told analysts and investors on Tuesday when asked about the Nike deal. He added that Nike has been transparent with Dick's in talking about the test with Amazon. "What they'll do ultimately — we'll deal with that when it happens."

The sporting goods retailer on Tuesday issued a softer outlook for 2017 to reflect its increased investments in pricing.

Dick's now expects to earn between $2.80 and $3 a share, on an adjusted basis, this fiscal year. Analysts surveyed by Thomson Reuters were calling for adjusted earnings of $3.09 per share.

Same-store sales for the year are now expected to be flat to down at a low single-digit rate. In 2016, Dick's same-store sales rose 3.5 percent.

"Dick's is another example of Amazon becoming the new middleman," SW Retail Advisors' Stacey Widlitz said in an interview with CNBC. "Here we go down the gross margin rabbit hole just in time for the holidays."

Looking ahead, Dick's said it plans to enhance its loyalty program "significantly" to get a bigger share of the customer's wallet and as competition intensifies.