The Ministry of Defence is writing to the chosen reservists this week and next to prepare them for possible action.
But teachers who are in the TA think it is unlikely that they will be included in the initial call-up.
Richard Cullen, who teaches maths and rugby at the Oratory School near Reading, said: "They will be looking at medical staff and drivers."
As a TA engineer, Mr Cullen thinks he would be more likely to be called on in the event of a lengthy conflict if damaged equipment needed shipping back to bases in Germany for repair.
Mr Cullen is a warrant officer and has been a TA member for 18 years, but says it is a "tremendously difficult" activity to combine with teaching.
Heather Lorch, 28, a German and French teacher at Ashton Park school, Bristol, is a vehicle mechanic in the 39th Signal Regiment. She thinks she is unlikely to get her call-up papers as she has only been in the TA for two years.
"The army will be calling on more experienced and battle-ready reservists, such as those who have just come out of the regular army. But there is always the possibility that I will be called up and I am ready for it," she said.
Biology teacher Rachel Donegan, 25, of Gordano comprehensive school in Bristol, enlisted in the TA last June. She has completed preliminary training as an engineer and will be eligible for call-up as soon as she finds time to complete her final two-week Royal Signals recruit course.
Signaller Donegan, said: "It is very hard to complete our training because it often requires weekends away, and at least a two-week block every year.
"The army practically shuts down during the school holidays so regular soldiers can be with their families. That means we can only do training if schools agree to give us time off during term-time."