The new Champions League format is affecting January transfer business, perhaps hinting there could be a rush of deals after the midweek fixtures are done.

Mike Keegan recently reported for the Daily Mail that the new Champions League format is having a knock-on effect on the January transfer window.
Agents and sources at clubs agree that the fact that the League Phase is still not finished has reduced the number of players willing to move. In the old system, we would know the outcome of the ‘Group Stage’ by now.
On top of that, any players that do move won’t be able to play for their new club in the Champions League until the knockout stages, as clubs can only register new players in February. There’s no point joining Arsenal to play against Girona on Wednesday, as you’d be ineligible.

It’s not just the Champions League either. The Europa League is the same, only concluding its League Phase this coming Thursday.
Most windows have a set of transfer dominoes, with one club’s deal for a player depending on the selling club finding a replacement of their own, and so on.
If many of the clubs in the Champions League and Europa League are delaying until they know their fate, that could end up affecting plenty of other deals indirectly.

But after Thursday, we’ll know which teams are through and which aren’t.
Players at eliminated clubs may be keen to continue their participation in the competition somewhere else, or may bring forward a planned summer move on the basis that they have nothing to play for with their current side in the second half of the campaign.
It’s going to be a frantic final few days before next Monday’s deadline, and we can only hope the right dominoes fall to allow Arsenal to make an attacking addition or two.