The Scottish FA has suspended Tonev, who is on loan from Premier League club Aston Villa, for seven games.
Logan claims that Tonev said "get your hands off me, you black shit", which Tonev disputes. However, a disciplinary tribunal that looked into the matter seems inclined to agree with Logan. The match in question occurred on September 13th and Tonev's hearing was delayed until Thursday because of his commitments to his national team, Bulgaria.
Celtic issued a statement supporting Tonev, and confirming his appeal.
"This was a very unfortunate case, but the club has accepted Aleksandar's explanation that he did not say the words that were alleged to have been said and that he is not a racist.
"We are, therefore, very disappointed by the outcome today and can confirm that Aleksandar will be appealing this decision."
Should that appeal fail, Celtic might not be keen on paying Tonev's wages for the rest of the season, while Aston Villa certainly won't be rushing to get him back.