Southampton are confident Jay Rodriguez will commit to a new long-term deal but the player will consider his options.
Wolfsburg director of sport Klaus Allofs says the club are keen to hold on to both Bas Dost and Nicklas Bendtner.
Petrucci has started both of Posh's npower Championship fixtures since joining the club on an initial month-long deal on January 9.
The 21-year-old midfielder told the club's official website: "I am very happy. I only signed for a month in the first place because it was my first loan spell.
"I didn't know what to expect. However, since the first few days I realised that I wanted to stay for longer and I am very pleased to be here until the end of the season."