The mechanism of subcategorization has been used for decades to account for many sorts of idiosyncratic behaviors of lexical items. We home in on the use of subcategorization for regulating the behaviors of individual exponents (morphs, vocabulary items), in particular, for infixation and suppletive allomorphy. We compare two distinct approaches, (a) enriched subcategorization , which takes there to be one mechanism governing both infixation and suppletive allomorphy, with their differences coming from enrichments to the (single) condition on an exponent’s realization, and (b) split subcategorization , which teases apart a mechanism governing infixation (a condition on an exponent’s position) from one governing suppletive allomorphy (a condition on the choice/insertion of an exponent). On the basis of a number of empirical and theoretical considerations, we argue for the latter approach: subcategorization at the exponent level must be deconstructed into (at least) two distinct conditions/mechanisms.