Bale and Modric's injuries are not looking good. First reports indicated that both players could miss Wednesday's match against Atlético de Madrid. Later, Modric was initially diagnosed with an sprained knee that would keep him out 5-6 weeks, and now reports from Spain say that the Croatian player is going to miss the remainder of the season. According to COPE, Modric left the Bernabéu in tears and crutches.
UPDATE: According to @AranchaMOBILE Modric left the Bernabéu in tears and with help of crutches.— Lucas Navarrete (@LucasNavarreteM) April 18, 2015
That same report indicates that Gareth Bale left the Bernabéu walking with crutches, meaning that his presence on Real Madrid's match against Atlético this Wednesday is very unlikely.
Both injuries will likely be confirmed soon enough, as both Bale and Modric will get some tests tomorrow and early Monday. If they are definitely out of the Derby, these are devastating losses for Real Madrid.