He is day to day
Well that isn't good news. It doesn't mean he is out for an extended amount of time like Marc Staal has been, but the Rangers are likely to be without Sauer for a little while.
What does this mean for the defense? Well, I think you need to consider splitting up Dan Girardi and Ryan McDonagh to give more support to Michael Del Zotto and Steve Eminger. Anton Stralman will get some time paired with Jeff Woywitka it seems like, but it will be interesting to see how much ice time they end up getting.