When Brice McCain was lost to a broken foot, the nickel corner/CB3 job became Brandon Harris' job. Though he's hardly been a world-beater in the secondary when he has played, the thought was that Alan Ball could potentially spell and/or replace Harris if he (Harris) struggled, either by playing in the slot himself or possibly shifting someone else to the slot by playing outside.
Harris did not look good on Monday night in New England; while he's far from alone in that respect, Ball's return would have given the Texans one more option to right a listing secondary. Tania Ganguli reports that we'll have to wait at least one more game for that, as Ball has been ruled out for Sunday's game against the Colts.
Newly-signed Stanford Routt probably still is not in a position to step in to shore up the secondary, so expect a bunch of Harris in the slot again at Reliant on Sunday.