Everybody's on the depth chart, but in Fitzspeak®, "doubtful" basically means "out". That's one of our starters and one person who has been playing heavily. VanHoose has really been NU's only competent defensive back, and Evans has looked okay, I suppose. You might have noticed that Nebraska started moving the ball pretty easily through the air as Saturday's game went on - that probably had something to do with injuries to two out of the top four cornerbacks.
Daniel Jones was already starting on the other side, and presumably Demetrius Dugar will take over at VanHoose's spot, although he was injured and didn't play this past week. To be honest, I don't know who the fifth person at corner would be - C.J. Bryant, a reserve who has played in all but two games thus far this year would be my guess. Can't be good for the Iowa game, although James Vandenberg didn't look capable of killing in the passing game against Penn State Saturday. NU fans have to hope VanHoose or Evans can play - the pass defense has been shaky as is.