Adidas Signs Houston Rockets Guard James Harden

Adidas AG on Thursday signed Houston Rockets shooting guard James Harden to a multiyear endorsement contract, a deal that shores up the German company's roster of American sports stars as it seeks to improve its U.S. market share.

The contract, which takes effect Oct. 1 and is set to include a signature product collection, is the highest-profile individual signing this year by Adidas, which also lost the chance to renew its contract with the University of Michigan athletics department and dropped out of the running to outfit the National Basketball Association.

Adidas has said it is trying to bolster its marketing around U.S. sports, especially individual stars.

Terms of the deal with Mr. Harden weren't disclosed.

Earlier this year, Adidas Chief Executive Herbert Hainer said its 11-year deal to outfit the NBA didn't help the company sell more footwear or connect with consumers. Instead, Adidas has pledged to double its roster of endorsed NBA players.

Other basketball stars who currently endorse Adidas products include Derrick Rose, Damian Lillard and John Wall.

Last year Adidas fell to third place in retail sales of sports apparel and footwear, behind rivals Nike Inc. and Under Armour Inc.

Oregon-based Nike commands more than 90% of the U.S. basketball shoe market and announced in June that it would take over the NBA outfitting contract in 2017.

Mr. Harden, who previously wore Nike shoes, is a three-time NBA all-star player and led the Rockets to the Western Conference finals in this year's NBA playoffs. With his distinctive beard, he is often recognized for making a pot-stirring motion with his hands when he is "cooking," or playing well, on the court.

The value of such an endorsement for athletic gear companies can take time to pay off.

"It usually takes years for the sales threshold to offset the marketing expense of the contract," said Matt Powell, sporting-goods industry analyst for NPD Group.

For the past six years, the distinction of the best-selling signature shoe for an active professional basketball player has belonged to Nike and LeBron James, according to Neil Schwartz, vice president of business development for industry tracker SportsOneSource.

Sportswear companies have been especially competitive in recent years in signing contracts with individual basketball players, a marketing strategy that can have mixed results, particularly as players' performances rise and fall on the court.

Under Armour's signing of Stephen Curry in 2013 is just beginning to show signs of momentum for the company's nascent basketball shoe business, after Mr. Curry became NBA MVP and led his Golden State Warriors to the league title this year.

In 2014, a bidding war between Nike and Under Armour over previous league MVP Kevin Durant led to Mr. Durant signing a 20-year Nike contract potentially worth $350 million, according to a person familiar with the matter.

Mr. Durant ended up missing much of the 2014-15 season with a foot injury.

"That's the concern—does somebody get hurt?" Mr. Powell said, of the risk for shoe companies in high-profile athlete sponsorships. "But of course, that's everyone's worry."

Write to Sara Germano at [e-mail]

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