Aberdeen's Jonny Hayes has failed to overturn his red card against Celtic and will serve a two-match ban.
The winger was shown a straight red for a foul on Mikael Lustig during his side's 2-1 win at Pittodrie last weekend.
Hayes appealed the sending-off with the Scottish Football Association, but a disciplinary tribunal has upheld referee Craig Thomson's decision.
And the 28-year-old will now sit out Sunday's trip to Hearts, which is live on Sky Sports, and next Wednesday's League Cup tie at Hibernian.
He said on social media: "Obviously gutted with the outcome today! Hearts away is always a fixture you look forward too. Hopefully the boys can continue the run."
Aberdeen go into the weekend with a five-point lead at the top of the Scottish Premiership.