The defender was not named in the matchday squad on Boxing Day, despite first-choice right-back Stephen Kelly being injured.
Boss Neil Redfearn revealed he was not injured himself and was left out over an issue with his contract, without going into any more detail.
The 32-year-old penned a one-year deal in the summer with the option of another and having made 20 league appearances, it is thought he will be able to trigger a second year if he makes one more.
Redfearn accepts that the issue needs sorting, but Buxton is unlikely to be involved in Tuesday's game at Fulham.
"It's a contractual thing that needs resolving," Redfearn said. "It's just one of those things."
Buxton made his debut in August's Capital One Cup win over Cambridge and has made 22 appearances in all.
