Zimmermann elected to become a free agent Wednesday.
Zimmermann cleared waivers after being removed from the Cardinals' 40-man roster, but he's chosen free agency rather than accepting an outright assignment. The southpaw could re-sign with St. Louis on a new minor-league contract, but he is free to negotiate with any team. Zimmermann permitted three earned runs in five innings in a bulk-relief appearance earlier this month in his lone outing for St. Louis.