As a rule, a player may not play in a UEFA club competition (i.e. UEFA
Champions League and UEFA Europa League, but not UEFA Super Cup) for
more than one club in the course of the same season. Exceptionally,
however, a player who has been fielded in the first, second or third qualifying
round of the UEFA Champions League or UEFA Europa League is entitled to
play in the UEFA Champions League or UEFA Europa League for another
club as from the group stage, provided that his former club did not qualify for
the group stage of either the UEFA Champions League or the UEFA Europa
League; moreover, as from the start of the round of 32 (round of 16 for UEFA
Champions League), a player can be registered in accordance with
paragraphs 18.18 to 18.21 below.
Por tanto si, podria jugar pero a partir de octavos. Estaba errado.