Portugal could be handed a two-legged clash with France for a place in Brazil with the two countries in separate four-team pots for the draw, which involves sides who finished second in their European qualifying groups.
Les Bleus and a Zlatan Ibrahimovic-inspired Sweden are the sides to avoid in the lower-ranked pot two, with Romania and Iceland, who have never been to a World Cup, the two weakest teams on paper.
Greece, Croatia and Ukraine join Portugal in pot one, meaning France have their work cut out to make the finals. The 1998 winners last failed to qualify in 1994.
A Portugal side complete with the fearsome presence of Ronaldo appear the toughest ask, but Ukraine pushed England all the way their group and it is hard to imagine too many in France would relish a November trip to Kiev.
Greece, who were beaten to top spot by Bosnia and Herzegovina on goal difference, and Croatia, who have a new coach in Niko Kovac and finished well adrift of Belgium, appear on paper the easier options.
France, now ranked 21st in the world, finished second to Spain.
Boss Didier Deschamps accepted the threat of Ronaldo made Portugal unwelcome opponents, but added on www.20minutes.fr: "Playing against Greece, Croatia and Ukraine, who all play as teams, will be no easier or simpler."
The draw for the four play-off matches will take place in Zurich at 1pm (BST).
The play-offs themselves will be played on November 15 and 19, with the first team drawn at home in the first leg. The away goals rule will apply.