I think someone has already mentioned it in this thread but our midweek game against Liverpool last season was happening whether or not we reached the League Cup Final. I think it was originally pencilled in for the Tuesday but moved back to the Wednesday once we'd both reached the Final.
The rearranged game from that weekends round of fixtures last season was the Newcastle (a) game, which was played on April 20th. I would expect Sky will ensure this rearranged fixture takes place at the business end of the season, the sceptic in me thought the game had been arranged for the League Cup Final weekend in the first place in the hope they'd be able to do exactly that!