The EFL rules require teams to field was is deemed a full strength team in all league games to maintain the integrity of the competition. For example, if we played Faxon in a game against a club in the bottom 3 and we lost, other clubs in the relegation zone may feel we gave our opponents an unfair advantage.
To add some more context, if Adam Davies gets injured or suspected we would be able to bring in another keeper on an emergency loan due to Faxon not being a "Professional goalkeeper' as defined by the EFL rules. If we have a game at the very end of the reason where the result can't effect our or any other clubs league position then we'd probably get away with it.
For outfield players it's easier to put 1 or 2 into the team, but if we suddenly drop an ex-international keeper for one who's never played a league game, that might not go down too well...