Things are getting ugly in Cleveland -- Odell Beckham Sr. is all but fed up with how his son is being used in the Browns offense ... posting an 11-minute-long video exposing Baker Mayfield for all the times he's missed a wide open OBJ.
Of course, Beckham Jr. had a career low in Sunday's loss against the Steelers -- only logging in one catch for six yards.
The performance appears to be the straw that broke the camel's back for OBS ... 'cause he went to Instagram to call out Mayfield by sharing a video titled, "Odell Beckham is Always Open for the Cleveland Browns in 2021.