Celtic have accused the Scottish Football Association of a "worrying lack of consistency" after Ryan Christie received a two-match ban for his foul on Alfredo Morelos.
A fast-track tribunal upheld the SFA compliance officer's assertion that Christie was guilty of violent conduct after catching the Rangers striker in the groin area with his hand.
Christie escaped with only a free-kick against him for the foul, after earlier being booked during Rangers' 2-1 win at Celtic Park on 29 December.
Celtic stated they were "astonished" by the SFA charge when it was announced on 31 December and they will take their concerns to the governing body.
A club statement read: "Celtic Football Club and Ryan Christie are extremely disappointed at the outcome of the hearing today.
"Given the recent treatment of Celtic players and the lack of sanctions being imposed on those responsible, the fact that a sanction has been imposed on Ryan for the incident in question demonstrates a worrying lack of consistency in the Scottish FA fast track process.
"Naturally, we will be contacting the Scottish FA regarding our concerns. Scottish football deserves a disciplinary process which is fair, consistent and fit for purpose."
Christie will miss Celtic's William Hill Scottish Cup clash with Partick Thistle on 18 January along with their Ladbrokes Premiership encounter at Kilmarnock four days later.
The ban triggers an extra one-match suspension because it is his second red-card offence of the season - he was sent off against Livingston - so he will also sit out the visit of Ross County on 25 January.
The Scotland international is recovering from groin surgery and was rated "touch and go" by assistant manager John Kennedy for the trip to Maryhill.
The Scottish champions called for a meeting with the SFA a year ago after Morelos escaped retrospective action for several incidents during the corresponding fixture, including flicking his hand into Christie's groin area.
Morelos could still be hit with retrospective action over the cut-throat gesture he made towards Celtic fans after he was sent off in the closing seconds of the game.
Christie's offence fell under fast-track procedures but gestures fall outside of those time limitations.
Rangers later claimed Morelos had been subjected to racial abuse and claimed his gesture was "used commonly throughout South America to indicate quite simply that something - in this case, the match - is finished".