Pastor Maldonado will move ten places down the Abu Dhabi grid next weekend.
The Venezuelan's last allocated Cosworth engine for the season, his eighth, was damaged when he retired from the race in India.
"Pastor will use a ninth engine in Abu Dhabi," confirmed technical boss Mark Gillan.
Before the Delhi race, Williams chairman Adam Parr urged engine partner Cosworth to up its game.
"We have had some reliability issues in the last three weekends, which our partner is working very hard to fix as soon as possible and, obviously, that's critically important for us," he said.
After the Interlagos finale late this month, the team is switching to Renault power for 2012.
"We are supplying engines to them because we think they have much greater potential than they are delivering today," said the French marque's chairman Carlos Ghosn, according to The Sun.