The goalkeeper has been attracting interest this summer, with both Nottingham Forest and French side Nantes seeing bids turned down.
New England Revolution rejecting the offers left Petrovic unhappy and he wants to be allowed to leave.
Now Chelsea are testing the MLS side’s resolve and have put in an offer of around £15m to take him to Stamford Bridge.
Whether that will be enough to convince New England Revolution to change their stance remains to be seen, but Chelsea are asking the question.
The MLS club would prefer to wait until the January transfer window to sell Petrovic.
Nottingham Forest remain keen on the goalkeeper as they look to sign options between the sticks before the transfer window closes.
Petrovic has caught the eye with his performances in the MLS and now wants the opportunity to test himself at a higher level.
