Sports Authority is prepping for store closing sales at its Sports Castle near downtown Denver and at least two other locations in the region as part of plans to shutter about 140 of its 450 stores, a source familiar with the company’s plans confirmed Wednesday.

Sports Authority plans to close stores at 1000 Broadway in Denver and 9000 E. Peakview Ave. in Greenwood Village, and the S.A. Elite store at the Twenty Ninth Street mall in Boulder, the source said.

It is unknown how many more of the 31 Colorado locations may be targeted for closure.

The shedding of stores comes as Sports Authority, the fourth-largest sporting goods retailer in the U.S., is reportedly on the brink of bankruptcy. Saddled with at least $643 million in debt, the company missed a $21 million interest payment in January and weeks later laid off 100 employees, mostly at its Englewood headquarters, to bolster its balance sheet.

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The interest payment’s 30-day grace period was up on Sunday.

Sports Authority posted notice of a 75 percent off liquidation sale on its website for the Boulder S.A. Elite store and shoppers were quick to notice.

“My roommate told me he’s getting shirts for $4,” said Lane Hamilton II, as headed to S.A. Elite, which will close Feb. 27. “I decided to get some deals.”

On Tuesday afternoon, employees at the Sports Castle were loading merchandise onto pallets to ship to the store near Park Meadows mall. Starting Friday, the Sports Castle will be a liquidation center. Employees told customers that the store will close at the end of its lease term.

Management at the Sports Castle store directed calls to Sports Authority’s corporate office. A company spokeswoman could not be reached for comment.

Mark Sidell, president of Gart Properties, which owns the Sports Castle building, declined to comment, stating he had no new information about Sports Authority’s plans.

Earlier Wednesday, CBSDFW in Dallas reported that employees across the metroplex there said they were told all 25 Texas Sports Authority stores will. At a store in Dallas, employees were seen packing goods into boxes as a large truck arrived to pick up merchandise, the Dallas Morning News reported.

Sports Authority, owned by private equity firm Leonard Green & Partners LP, was negotiating with bondholders on a deal to reorganize through Chapter 11, Bloomberg previously reported.

In 2003, Gart Sports, the venerable Colorado sporting goods company, merged with Florida-based Sports Authority. The $500 million deal combined the two publicly traded companies under Sports Authority’s flag at Gart Sports’ headquarters in Englewood.

Three years later, a Leonard Green & Partners-led group snapped up Sports Authority for $1.3 billion, taking it private in the process.

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In the past decade, Sports Authority has grown in the U.S. and Puerto Rico while also taking on a 20-year, $60 million naming-rights deal to replace Invesco as the sponsor of Mile High Stadium, the Denver Broncos’ home field.

The next stadium payment of $3.6 million is due on Aug. 1.

Sports Authority has made its payments “on time and in full since day one,” Matt Sugar, the spokesman for Denver’s Metropolitan Football Stadium District, said earlier this year.

Daily Camera photo editor Paul Aiken contributed to this report.

Alicia Wallace: 303-954-1939, awallace@denverpost.com or @aliciawallace