"Pablo Daniel Osvaldo is in Turin for a medical visit," the club wrote on its official Twitter feed, before posting a picture of the striker arriving in the city on its website.
Italian media have reported that the loan deal is costing Juventus 400,000 euro (329,426.77 pounds), with the Serie A leaders having the option to buy the forward for 18 million euro ($24.4 million).
Osvaldo has only scored three Premier League goals since moving to Southampton from AS Roma in the summer, and a recent disciplinary row has hastened his exit.
The Italian international striker was suspended for two weeks by the Saints following a training ground altercation with team-mate Jose Fonte, and by returning to Italy wants to ensure his place in Cesare Prandelli's World Cup squad.
Juventus are six points clear at the top of Serie A, and on Sunday (1945 GMT) host bitter rivals Inter Milan, who they beat to Osvaldo's signature.
(Reporting by Terry Daley, editing by Steve Tongue)
