Wilson has until December 14 to select his second driver for the 2013-opening Monte Carlo Rally.
He is currently considering numerous names for the role and admits he might run more than one driver over the season in the second factory Ford Fiesta RS WRC.
Ostberg sealed a full-time seat with M-Sport's new Qatar-backed team in late November.
"I've got some time now and I'm going to take it," Wilson said.
"We've still got plenty to sort out before we get around to announcing who it'll be.
"The one thing I will say is that my preference is to have one driver doing all the rallies, this is better for consistency and for the fight for the championship."
Ford's 2012 lead driver Jari-Matti Latvala has departed for Volkswagen Motorsport and Petter Solberg, Wilson's second driver this season, has stated he will not pay to remain in the Fiesta.
It remains to be seen whether backers can be found to fund another year for the Norwegian.
Other possible drivers include Evgeny Novikov, Thierry Neuville and Ott Tanak.