SOUTH BEND, Ind. — Under Armour Inc. CEO Kevin Plank recalls sleeping in the visiting locker room at Notre Dame Stadium back in 1997, invited to the game by Georgia Tech staff and forced to bunker down because he didn’t have a hotel room.

Back then, his company was about a year old and he was excited to see the Yellow Jackets take the field in Under Armour apparel.

On Tuesday, Plank was back in South Bend to announce a 10-year apparel deal with the Fighting Irish that Notre Dame athletic director Jack Swarbrick described as the largest deal of its kind in the history of college athletics.

Michigan’s eight-year contract worth with $8.2 million annually is generally believed to have been the largest until Notre Dame’s deal. Swarbrick wouldn’t disclose terms.

“There’s been a lot of speculation about whether this deal would top $100 million,” said Nancy Lough, a professor of higher education at the University of Nevada Las Vegas and president of the Sport Marketing Association.

Adidas, which began providing shoes to Notre Dame in 1997, issued a statement saying it would no longer partner with Notre Dame after the 2013-14 season.

“As with every business decision, we weigh our investment against the value to our brand,” spokesman Michael Ehrlich said.

Swarbrick said it was important for Notre Dame to have such a deal to get through what he called a period of change in college athletics “unlike any of us have ever lived through.” He mentioned the change from the BCS to a playoff system in football and conference realignment in all sports that saw Notre Dame move from the Big East to the Atlantic Coast Conference last year.

Sports marketing experts say the deal was important for Baltimore-based Under Armour.

“This spreads their footprint further,” said Rick Burton, a sports marketing professor at Syracuse. “With Notre Dame being such an emblematic university with such a national fan base, I think this fully signals that Under Armour is in the game. That they’re a big-time player in terms of going after attractive university contracts.”

Under Armour is a relative newcomer to the industry so it has had to build its reputation on innovation, Lough said.

“They simply weren’t going to get a big school right out of the gate,” she said. “They’re young still, but to add Notre Dame at this stage is a real big statement for where the brand is going.”

Swarbrick said the deal includes an option for Notre Dame to take a portion of the cash component from the deal in Under Armour stock. He said he was impressed by Under Armour’s commitment to technology and said the deal would provide Notre Dame with something it has been missing.

“For us to marry our tradition with one of the great entrepreneurial stories in recent time in this country is exciting for me,” he said. “I think it will impact our culture in direct ways. Make us more creative, more inventive, allow us to move more quickly and to be fundamentally entrepreneurial.”

He said the university has asked Under Armour to make Notre Dame its laboratory for new technology.

Plank said the deal was a “game-changing event” for the company.

“It puts us on a completely different level, and frankly, we’re ready for that level,” he said.

Maryland was the first football team to be outfitted in Under Armour gear in 2004 and the company’s first Division I all-school partnership was with Auburn in 2006. Notre Dame is the 13th school to sign with Under Armour.

Plank said he didn’t expect any major changes in how Notre Dame uniforms look.

“We’re not anticipating doing anything unusual, crazy. We need to honor and respect the history of the university,” he said.

Burton said the deal signals to Nike, which has the most deals with Division I schools, that it had “better clamp down on the schools that you really care about.” Burton said it also will be interesting to see how Adidas responds.

“Theoretically, whatever Adidas was paying Notre Dame is now available to be paid somewhere else,” he said.