Zubar has returned to parent club Bournemouth for treatment on a knee injury he sustained during last week's 4-1 loss at Notts County and Shakers boss Kevin Blackwell believes the prognosis is not good.
"If we get him back at any point this season, it will be a bonus," he said. "We don't know the full extent of the injury yet and probably won't until next week, but we think he is out for the season."
Blackwell could opt to recall Efe Sodje or Mark Hughes from their respective loan spells at Barrow and Accrington in the coming weeks but offered praise for Ashley Eastham and Ethan Ebanks-Landell, both of whom recovered from a torrid time at Meadow Lane to star at the heart of defence in Tuesday's shock 1-0 win over Swindon.
"The two young centre-backs were awesome," he told the Bury Times. "For the mistakes they made at Notts County, they thoroughly redeemed themselves."
Long-term absentees Phil Picken (knee), Adam Lockwood (knee) and Shane Byrne (blood disorder) remain sidelined.