Oklahoma State star running back Ollie Gordon II, who scored 21 rushing touchdowns last season, was arrested over the weekend ... after authorities said they believed he was driving drunk.
In court documents, obtained by TMZ Sports, an Oklahoma Highway Patrol trooper wrote they pulled over Gordon's black 2024 Cadillac at around 2:30 AM on Sunday ... after they say they saw it swerving and speeding on a local interstate.
During the ensuing stop, the trooper said in the docs "an odor associated with an alcoholic beverage" emanated from Gordon's ride ... so they conducted an interview with the 20-year-old football player.
The OHP said Gordon eventually admitted to consuming one alcoholic beverage before getting behind the wheel. They also claim he told them he had two open containers of booze in his vehicle -- and a search of his car later revealed a half-full bottle of lemonade vodka and a half-full bottle of tequila.
Gordon then allegedly refused to participate in field sobriety tests ... which the trooper stated in the docs they believed was in an effort "to hide evidence of intoxication."
Gordon was ultimately placed under arrest and booked on several charges -- including DUI under 21 years of age.
At the jail, authorities say Gordon's blood alcohol level samples came back .11 and .10 -- just above the state's legal .08 limit.
We've reached out to OSU for comment ... and they told us "we are aware of the situation and have no further comment at this time."
Gordon -- who rushed for 1,732 yards and won the Doak Walker Award last season -- is expected to have a huge junior season with the Cowboys following a historic breakout sophomore campaign.