But the central bank will reassure markets it is nowhere near an exit from years of ultra-loose policy given risks to the inflation outlook, such as uncertainty on how quickly companies would raise wages to meet labour shortages, the sources said.
"The economy is sustaining momentum for inflation to reach 2 percent. But the pick-up in inflation remains modest," said one of the sources, a view echoed by two more sources.
The BoJ will conduct a quarterly review of its growth and price forecasts at a rate review on April 26-27, when it is expected to keep monetary policy unchanged.
There had been some market speculation that the BoJ would downgrade its 2019 inflation forecast. It will be releasing its 2020 projection for the first time.