Sato Masaki will not participate in any Hello! Project activities due to medical reasons for two months.
Sato had been diagnosed with a lumbar disc herniation some time ago. Because of this she experiences increasing lower back pain. On doctor’s orders she will refrain from any physically exhausting activities until at least the end of February.
A decision as to the resumption of her activities will be made in mid- to late February.
Source: Hello! Project