If you haven't heard yet, Fenerbahce are out of the UEFA Champions League due to their involvement in a match fixing scandal. This will leave the draw for the Champions League group stages with 31 teams. At the moment, no one knows how Fener will be replaced in the draw and there is no clear-cut rule in place that explicitly states how this will be done. There are all kinds of rumors circulating at the moment, but nothing has been decided. There are a lot of different ways UEFA could go about this, so let's sort through all of them.
If UEFA wants to take the next best Turkish team not heavily involved in the scandal
Then Bursaspor would be the team to take Fenerbahce's place. They finished third in the Turkish Super Lig last season.
If UEFA wants to take the team eliminated in the qualifying round with the highest club coefficient
A number of things can happen. Half of the matches are still yet to finish in this round. The clubs who have been eliminated or could be eliminated that could possibly replace Fener, in order of club coefficient, are Arsenal, Olympique Lyonnais, Benfica, FC Copenhagen and FC Twente. Benfica and Twente play each other, so rankings beyond them are irrelevant.
If UEFA wants to take the eliminated champion from the highest ranked league
The teams who could potentially go through are, in order, FC Copenhagen, SK Sturm Graz and Maccabi Haifa. Both Copenhagen and Sturm Graz play Wednesday night. Maccabi Haifa lost on Tuesday.
If UEFA wants to take the eliminated team from the highest ranked league
The loser of the tie between Arsenal and Udinese will progress to the group stages despite their loss.
It would be pretty surprising if UEFA revealed who will replace Fenerbahce before all games are completed, as they won't want to unfairly affect competition. This story will be updated whenever new information comes in.