The controversial striker was about to return from a three-match FA ban imposed at the start of January, but will now miss a further three games after being sanctioned by his club
The Saints have not gone into specifics about the issue, but insisted that they have taken "swift and proper action" against the Italy striker, who will now miss games against Yeovil, Arsenal and Fulham.
A statement published on the club's website reads: "Southampton Football Club has today suspended striker Dani Osvaldo for two weeks, following an incident at the Club’s Staplewood training ground.
"The Club has taken swift and proper action for what it considers a breach of the conduct expected of its players.
"Southampton will be making no further comment on this matter."
Osvaldo was banned for three matches and fined £40,000 by the FA earlier in January for sparking a touchline row during the 1-1 draw against Newcastle in December. His latest ban, this time imposed by the club, means he will miss six consecutive games through indiscipline.
The striker signed from Roma in August 2013 for around £12 million plus bonuses, but has scored just three goals in 13 Premier League matches this season.
The Argentina-born Italy international has a chequered disciplinary history and was involved in a number of run-ins before moving to England
Following Roma's defeat to Lazio in the Coppa Italia last May, Osvaldo insulted then coach Aurelio Andreazzoli and punched an advertising hoarding, before hitting out at Andreazzoli on Twitter, urging him to "Go celebrate with Lazio".
He was also banned for 10 days for a dressing room bust-up with Erik Lamela in 2011 after the Argentine winger, now at Tottenham, failed to pass him the ball during defeat against Udinese.
It would not be the first or last time that he angered the Italian club, who were not impressed when he skipped a winter training camp in the United States a year ago. The fans also pelted his car with eggs and rocks after he jumped ahead of club legend Francesco Totti to take a penalty, only to miss.