Just for some context here from earlier rounds this season
Sheff Wed v Rochdale 9,045
Derby v West Brom 10,638
Watford v MK Dons sounds like a derby to me 8,891
West Brom v Sheff Utd 6,747
Blackburn v Hartlepool 6,844
Middlesbrough v Barnsley 9,361
Sheff Wed v Sunderland 8,412
Blackpool v Barrow 4,972
Huddersfield v Preston 5,550
Cardiff v Portsmouth 6,303
Reading v Stevenage 4,230