Gale, whose outstanding form in 2012 earned him a call-up for England Knights, will have an operation on the ankle he damaged while playing for the Knights and will be sidelined for eight weeks.
The former London Broncos half-back had his foot immobilised immediately after suffering the injury in October but further scans have revealed he needs an operation.
Bradford say it is not the same ankle he damaged last season.
Gale could recover fitness in time for the Bulls' opening match of Super League XVIII on February 3 but Bateman is likely to miss the first month of the new campaign after being told he needs a shoulder reconstruction.
Bateman, who has been handed the number 11 jersey for 2013, sustained the injury at the end of last season but was initially told that rest would cure the problem.
However, the injury flared up again when he began full contact training and he will have the operation on Monday and be sidelined for 12 weeks.
Bulls coach Francis Cummins said: "It's really disappointing for both players as well as the club.
"Pre-season training is going very well and to suffer these setbacks is a blow.
"However it is better to find out now than at the start of the season and both players will be working hard to get back to full fitness as soon as possible."