Sulzberger replaces Michael Rogers, who is suffering from tonsillitis and was forced to drop out. It is the first time Rogers has missed the Worlds in 13 years.
"It's always a blow to lose a rider of the calibre of Michael Rogers from a national team," said Cycling Australia National Performance Director, Kevin Tabotta. "Michael adds so much value physically and tactically to our worlds teams.
"This season has been one of his best and his experience will be missed on Sunday."
Tabotta had to choose between Garmin-Sharp's Nathan Haas and Sulzberger, who will take part in his fourth road world championships. He claimed a silver medal as an under 23 in 2007.
"We needed to bring in someone who we know has the experience and current form to provide the support needed for team plan," said Tabotta. "Wes has world championship and big race experience and we're confident he will provide solid back up for the team leaders in their pursuit of a podium result."
Sulzberger said via Twitter that he was "very honoured to have been given the position", while Haas wished him and the team luck and said, "Would love to have raced for Australia at worlds, not meant to be this year."
Australia will be represented in the 267km road race on Sunday by Orica-GreenEdge riders Simon Clarke, Allan Davis, Simon Gerrans and Sulzberger, as well as Adam Hansen (Lotto-Belisol), Heinrich Haussler (Garmin-Sharp), Michael Matthews (Rabobank), Richie Porte (Sky) and David Tanner (Saxo Bank-Tinkoff).
In the time trial, Luke Durbridge and Cameron Meyer (both Orica-GreenEdge) will take part for Australia.