Rene Sain suffers from mononucleosis, so she'll be out for a while. I guess for the time being Wiesbaden will continue with Guilliams as libero, it worked well in the last two matches.
Oh...I remember Bryanna Weiskircher had the same in the preparations for Dresden a few years ago and they had to end the contract.
I could imagine that they try to find a replacement for her. Guilliams did amazing but she's also needed as OH. They actually have a 2nd libero but she seems to play mostly for their 2nd team.