This study addresses the transitive intransitive alternation in verb formation based on both thematic and morphological relations between words. I examine cases of puzzling mismatch between the thematic derivation of predicates via valence changing operations and the morphological form they exhibit. These are cases, where the thematic relation between two verbal instances shows that A is derived from B, while the morphological relation between them indicates that B is formed on the basis of A. To resolve this conflict, I rely on the notion of frozen lexical entries and on the historical relations between the relevant forms. I argue that while form A is indeed thematically derived from B, B existed in the lexicon as a frozen entry. Further, form A entered the actual vocabulary first and was used for the morphological formation of B. (C) 2013 Elsevier B.V. All rights reserved.