Except for a diplomatic mission in 590 to the recently deposed Persian ruler Khosrau II (r. 590–628), who had taken refuge in Roman territory, Philippicus disappears from the scene for several years. In 598, he was briefly appointed general in the ongoing war in the Balkans, and is credited by some sources with a victory over the Avars in Thrace, although this is most likely due to a confusion with general Priscus.