The move comes after the Rockies officially announced the signing of closer Wade Davis. The team had a full 40-man roster, and the addition of Davis required somebody be removed. The Rockies added Carle to the 40-man roster prior to the 2017 season to protect him from being taken in the Rule 5 draft. He only pitched four major-league innings, however. Carle, 26, spent most of the season in Triple-A, where he posted a 5.37 ERA in 62 innings pitched.
The Rockies now have a seven-day window in which they have to either trade Carle or be place him on waivers. If he goes on waivers and somebody claims him, he belongs to that team. If nobody claims him, the Rockies can either release Carle or outright him to the minor-leagues. Carle was only likely to play an emergency relief role for the Rockies in 2018, and he could very well still be in that role if he passes through waivers and the team chooses to keep him in the system.