Engineering work taking place somewhere between Stalybridge and Victoria on three weekends 30/31 August, 6/7 September, 13/14 September. Trains only going as far as Stalybridge. Although the timetable shows times for a connecting bus from Stalybridge to Victoria, there will still be half-hourly trains from Stalybridge to/from Piccadilly as an alternative. These might be more convenient, especially on 30th August when Man City are playing at home and the buses might struggle to keep to their published timetable.
http://www.northernrail.org/pdfs/trackworks/2309_Man-Huddersfield.pdf