Midfielder Davies (knee) was back on the bench against Norwich on Saturday and is hoping to make his first appearance since November while centre-back Mills was absent against the Canaries with an ankle problem.
Persistent hamstring troubles have sidelined Craig Davies again while a similar issue is keeping midfielder Darren Pratley on the sidelines too.
Wanderers have had a lengthy injury list for some time now and it includes Max Clayton (ankle), Zach Clough (shoulder), David Wheater (hamstring), Marc Tierney (broken leg) and Simeon Slavchev (ankle).
Charlton skipper Johnnie Jackson is on the mend after a leg injury but the trip will probably come too soon.
Callum Harriott is set to miss out again with an ankle problem and fellow winger Franck Moussa is unlikely to appear before the end of the season due a knee injury.
Boss Guy Luzon could make changes following Saturday’s 1-1 draw at Sheffield Wednesday with Frederic Bulot, Alou Diarra and Tony Watt among those pushing for recalls.
Midfielder Chris Eagles will be hoping to start against his former club.