Current M-Sport Ford driver Ostberg is on Citroen's shopping list, and runs seventh on this weekend's event at present.
With the silly season set to be resolved before next month's Rally GB, Ostberg said Sunday's gravel stages were the final chance for drivers without contracts to show what they can do.
"We're all on the list [of who goes where next year]," said Ostberg, "and I think it depends a little bit on what happens today. It's a very important day."
Ostberg's team principal Malcolm Wilson agreed with his driver.
"I think Mads is right. I just said to his engineer, this is an important day for him - he really needs to get back on it," said Wilson.
"He's in a perfect road position and he needs to send out a clear message to all of us.
"It's the same for Mikko [Hirvonen] as well.
"They're not going to win the rally but they have a lot to fight for to prove their value."
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