The service allows users to order a private vehicle, taxi, or peer-to-peer car service through a mobile app.
"The NFLPA is committed to serving our membership both on and off the field," NFLPA Executive Director DeMaurice Smith said in a press release. "We view the partnership with Uber as an innovative way for players to have access to professional transportation while also pledging to each other, to their families, and to the community to make responsible decisions."
Smith said during a press call that Uber will provide another safe alternative for players, noting a reported drunk driving accident that occurred early this year in Texas that claimed the life of a player.
Uber and the union will give all active players personalized keychain cards with $200 in ride credits, according to The New York Times. Players will also get first-time rider promo cards to give to their friends and family.
The contract, which begins this month, is good for the 2013-2014 NFL season. Uber operates in 17 of the NFL's 31 cities including Pro Bowl host Honolulu.
Uber CEO Travis Kalanick said the on-demand car service already serves individual NFL players, but this is Uber's first professional sports account of this magnitude.
"A lot of our customers happen to be NFL players, but there's a whole bunch more that could, and should in many cases, be using this for safety aspects," he said during a press call.
More high-profile business accounts are probably coming for the company. Uber recently expanded its executive team with three new hires, including a new senior vice president of business who's in charge of making business partnerships.
Updated, 8:17 a.m. PT: Added more background and information from press conference.