Kevin Maher has lost his appeal against his red card he picked up at Colchester last week.
The midfielder branded Colchester's Karl Duguid a cheat after he went down clutching his face following an off-the-ball clash with Maher.
Southend had hoped video evidence would be enough to win the case, but the FA have rejected the appeal.
Meanwhile, defender Adam Barrett is still struggling with a stomach complaint.
He has been suffering for the last month with the problem but he had hoped to make a comeback this week - but the complaint has sidelined him again.
"It's been disappointing to have been forced back into the treatment room with my stomach problem this week," he said.
"The injury flared up again following the reserve team match with Oxford and there was just no way I could train after that.
"There were concerns that it may be a Gilmore's groin or a hernia and that would have meant having an operation and being out for around four to six weeks.
"Because of that we went to see a specialist on Monday but he said that I had just torn a stomach muscle and had tried to come back too early.
"He told me to rest up for the next two weeks and then I should be okay to return after that.
"It was obviously still disappointing to be ruled out for that amount of time but I'm also well aware of the fact that it could have been much worse.
"Adding to the frustrations the side have lost the last couple of matches and I must admit that I'm already beginning to climb the walls of the physio's room because I want to be out there playing so badly."