This is an underwhelming performance for Sanders if true. Frankly I don't understand why the Clinton campaign doesn't contest the state more aggressively, a win in Wisconsin will completely discredit Sanders as a serious candidate, at least in the eyes of the media.
Well the harder that try the bigger deal it is if they lose. Sanders it out spending them significantly and has 3 events in WI today alone. Clinton has no more events in WI before the primary. If it is close they can spin it as a win.
I think they are looking more at NY and PA to be the knockout. Sanders has to win at least one to prove he is viable.