Hibs have failed in their attempt to overturn the red card shown to Ryan Porteous in Saturday's 3-1 defeat against Aberdeen and he will now serve an extended four-match ban.
Porteous was dismissed by referee Alan Muir after fouling Ross McCrorie in an incident that led to the Dons being awarded a penalty from which they went 2-1 ahead.
Hibs manager Shaun Maloney admitted the spot-kick decision was correct but claimed his player should not have been sent off because he made a genuine attempt to win the ball.
"For me it was incorrect, he's gone for the ball," said Maloney after the match. "A definite penalty, but the rules are that the referee shouldn't send him off. It's disappointing because it had a big effect on the game.
"It's a penalty but he made a genuine attempt to get the ball so he shouldn't be red carded."
The Easter Road side appealed the red card on Tuesday, but have now confirmed it has been unsuccessful.
Due to previous suspensions this season Porteous will now serve a three match ban with another added.
A Hibs spokesperson said: "We can confirm that our appeal against Ryan Porteous' sending off against Aberdeen has been unsuccessful.
"Our centre-back was dismissed after giving away a penalty in our defeat at Pittodrie.
"After receiving our appeal, we are disappointed that the SFA have deemed that there wasn't a possibility for Ryan to play the ball successfully and have increased his suspension to four league games.
"That means he will miss our games against Dundee United and Hearts, alongside the first two matches after the split.
"He will, however, be available for our Scottish Cup Semi-Final against Hearts at Hampden."