Following a previous booking for blocking off Jason Holt earlier in the second period, McArdle was given his marching orders in the final minute of normal time after another caution for knocking over United striker Steven Davies.
Dismissals due to a second bookable offence usually carry a one-game suspension but McArdle's ban will be doubled to two matches given the fact that he has already been sent off at Oldham Athletic earlier this season.
As such, McArdle will now miss Tuesday's trip to Scunthorpe United and next Saturday's final home game of the season against Barnsley.