Since his adopted father Kinnaga was stopped from his duties because of an accusation of murder in 1138, Sadanaga was implicated in it and was stopped from shinji gubu (to be in attendance on divine services).
保延4年（1138年）、養父公長が殺人の罪に問われて職務を停止されたため、定長も連座して神事供奉を停止された。