The Kansas City Chiefs announced on Tuesday of this week that 5,500 tickets remained for Sunday's game. The team had to sell them by noon today to avoid a blackout. However,the NFL can grant an extension, like they did last weekend, to sell the remaining tickets.
The league generally grants an extension if a sellout is likely.
But, as of this posting, there's been no announcement from the Chiefs or the NFL on the blackout.
Josh Looney of KCChiefs.com reports, "Yes, the noon deadline has come and gone..[C]hiefs still working with league regarding the possible blackout on [S]unday."