I don't think it's been postponed, Udine is likely to be given a 3-0 win. We can actually see their starting 11 on Twitter even though there won't be a match. I mean, it's been about a year after the Juve-Napoli controversy, and i just don't understand why is it so hard for Serie A to simply postpone the match like they would do almost everywhere else...mind boggling!
source: google-translated from: https://www.tuttonapoli.net/le-altre-di-a/udinese-salernitana-la-lega-serie-a-non-rinvia-friulani-e-arbitri-dovranno-presentarsi-490475
edit; "Awaiting Arrival Of Away Team"