On the back burner phrase
If something is on the back burner, it is not being done, considered, or handled now but left to be done or thought about in the future.
We have to put this project on the back burner because there are several other projects that need our immediate attention.
I think the plans for a new factory should be on the back burner until the improvement in the economy.
Because of appaling weather conditions, all airline's schedules are on the back burner.
The metaphor here is from cooking on a stove with several burners of varying heat: food cooking at a lower temperature on a back burner receives or requires less frequent attention than that cooking at a high temperature on a front burner.