Jameis Winston is adamantly denying grabbing a female Uber driver by the crotch during a March 2016 ride despite a complaint the driver made to the company ... but now the NFL is investigating.
The woman who identifies herself as Kate told BuzzFeed she picked Jameis up from a nightlife area in Scottsdale, Arizona around 2 AM -- and Jameis got in the front passenger seat.
During the ride, Kate says the Tampa Bay Bucs star was out of control -- screaming homophobic comments to pedestrians -- before requesting a stop at a Mexican restaurant.
While in the drive-thru line to pick up food, Kate says Winston "reached over and put his fingers on my crotch. It wasn't accidental."
Kate says she wasn't just "creeped out" ... "I was frozen."
After the ride, Kate says she filed a complaint with Uber but did not go to police because she feared backlash from NFL fans.
Winston's camp says the allegations are completely false -- "We categorically deny this allegation. It is our understanding the Uber driver was unable to identify the specific individual who allegedly touched this driver inappropriately. The only reason his name is being dragged in to this is that his Uber account was used to call the ride."
Uber says Jameis has been banned from using the app in the future.
The NFL has confirmed to TMZ Sports the league is investigating the situation. An NFL rep tells us, "The allegation was shared with the NFL and we have reached out to Uber to request any information they may have."