Nike Expected to Win NFL Apparel Rights

National Football League owners will be presented with a proposal tomorrow that will award the league's apparel and sideline rights to Nike, multiple sources have confirmed to CNBC.

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The five-year deal was first reported Monday afternoon by Sports Business Daily.

Under the terms of the agreement, the NFL will award the valuable rights to Nike, which lost out to Reebok in 2001.

Reebok reportedly paid $300 million for the 10-year rights that expire at the end of next season.

Terms are not known, but the bidding was hotly contested between Nike , Adidas—which now owns Reebok—and Under Armour .

Asked whether a deal is in place, a Nike official said: "We are involved with the NFL negotiations but can not comment on ongoing discussions."

If the new deal is approved, Under Armour would continue as the apparel supplier of the league's combine.

Adidas, which currently has rights to the National Basketball Association, will likely be on the outside looking in, which Adidas CEO Herbert Hainer told CNBC last month he'd be content with.

"We decided how much we were willing to pay," Hainer said. "We think it’s reasonable and our intention is to try to keep the NFL as a property. But if somebody bids higher than us then we’ll accept that...So if we lose the NFL, it won’t make or break our company."

Buffalo-based private hat maker New Era will be presented as the official cap of the league.

If Nike prevails as expected, the industry will undoubtedly closely watch how fans react. Will jersey purchases slow during Reebok's lame duck season next year in anticipation of Nike's changes for the '12-'13 season?

Shares of Nike were about 3 percent higher in extended trading after finishing the regular session slightly lower. Get after-hours Nike quotes here.