MK Dons have decided not to appeal against Jason Puncheon's red card in the 1-1 draw against Colchester United.
The midfielder, who was making his debut for Roberto di Matteo's side following his loan switch from Plymouth Argyle, was shown a straight red card on the hour mark for a challenge on U's skipper Dean Hammond and will be suspended for three matches.
The former Barnet player will definitely miss this month's games against Carlisle United and Peterborough United.
If Millwall progress to the fourth round of the FA Cup, Puncheon will be banned for the visit of Leyton Orient to stadium:mk.
However, if the Lions fail to beat Crewe Alexandra in the third round, the midfielder will miss the League One game against Kenny Jackett's team.