A "freak incident" has resulted in a foot injury that has ruled State of Origin prop Paul Vaughan out of the remainder of the NRL season for St George Illawarra Dragons.

Vaughan recently started training after damaging his right ankle against New Zealand Warriors on August 4 and was named among the reserves for Sunday's meeting with Canterbury Bulldogs.

However, the New South Wales Blues front-rower will not feature again this year for the Dragons, who offered no further details on what caused his latest setback.

"Paul suffered a season-ending injury to his foot in a freak incident at training," said the Dragons' head of athletic performance Nathan Pickworth.

"Paul's foot injury occurred on the opposite leg to the one he previously suffered against the New Zealand Warriors in Round 21."

Vaughan said: "I'm devastated that my season has come to an end so suddenly.

"However, I'll continue to support the boys for the rest of the year, and I look forward to coming back bigger and better in 2019."

The Dragons remain in contention for the minor premiership with two matches remaining, but they only sit fourth ahead of Penrith Panthers and Cronulla Sharks on points difference.