Dallas Cowboys defensive lineman Daniel Ross was arrested in Frisco, TX on Wednesday ... after cops allegedly found weed and a gun in his car.
TMZ Sports has confirmed ... the 26-year-old (who signed a 1-year deal with Dallas in the offseason) was pulled over by Frisco PD early Wednesday morning during a routine traffic stop ... and at some point, cops say they found the weed and the firearm.
We're working on getting more info about the incident.
Ross hasn't played a down of football this season -- he was placed on Injured Reserve back in August with a shoulder injury.