Grimm's law
This sequence would lead to the same end result. This variety of Grimm's law is often suggested in the context of the glottalic theory of Proto-Indo-European, which is followed by a minority of linguists. This theoretical framework assumes that "voiced stops" in PIE were actually voiceless to begin with, so that the second phase did not actually exist as such, or was not actually devoicing but a loss of some other articulatory feature such as glottalization or ejectiveness. This alternative sequence also accounts for the phonetics of Verner's law (see below), which are easier to explain within the glottalic theory framework when Grimm's law is formulated in this manner. Additionally, a change from aspirated stops to fricatives is known to have happened in the transition between Proto-Indo-European and Proto-Italic, so represents a plausible potential change from Proto-Indo-European to Proto-Germanic.