As before and after his abscondences and returns there were big battles (Battle of Sekigahara and The Siege of Osaka), there is a theory that he was an intelligence agent of the Sanada clan, however, this there is no documented evidence that could support this theory.
出奔・帰参の前後に大きな戦い（関ヶ原・大坂の陣）があることから、真田氏の諜報官であったとする説があるが、証拠になるような史料は見当たらない。