Charlie Austin launched an astonishing rant at boss Ralph Hasenhuttl after being frozen out, according to The Sun.
His team-mates were stunned as the outcast striker accused the Saints manager of being 'disrespectful'.
The 30-year-old striker launched his tirade after being told he would not travel with the first team during pre-season.
Austin has been told to train with the Under-23s as the club try to offload him during the summer transfer window.
The striker, who has one year left on his current contract, has reportedly snubbed a move to West Brom.