McCarthy’s performances for loan club Wycombe Wanderers have seen him included as one of the four nominees alongside Gareth Evans, John Lundstram and Matty Taylor.
The 20 year-old featured in six games during the course of December, helping Wycombe to three wins and progression in the Emirates FA Cup.
The defender also scored in the 2-1 win against Oxford United just before Christmas, while he helped keep clean sheets against Luton Town and Crawley Town.
McCarthy extended his loan with the Chairboys on Monday until the end of January. The winner of the Player of the Month award will be announced on Friday 8th January.