Wrexham have lost their appeal against midfielder Rob Evans' red card during Tuesday's 0-0 draw to Bristol Rovers in the Conference.
Referee Ross Joyce sent Evans, 19, off shortly before half-time following a challenge on Matty Taylor.
Evans will now serve a three-match ban starting with Saturday's game against Maidstone United.
"We thought we had a valid case but we have to get on with it," manager Kevin Wilkin said.
Evans will also miss the FA Trophy tie at Southport on 13 December.
His third match suspended will then be either a possible cup replay or the Conference match with Dartford.
Wrexham also received two red cards in the defeat to Altrincham in November.
After Tuesday's game against Bristol Rovers, Wilkin said: "I think we're getting a raw deal.
"The referee shouldn't be the most important person on the field.
"If we're getting people sent off for dissent and those sort of things then clearly I can do something about that.
"I can't stop my players tackling and I'm not going to stop them tackling."