The Rangers placed Farrell (jaw) on the 60-day injured list Thursday.
The transaction opens up an extra spot on the 40-man roster and confirms that Farrell will be sidelined until at least late May while he works to regain weight and ease into a throwing program after he required surgery earlier this month to address a fractured jaw. Farrell isn't expected to fill a high-leverage role out of the Texas bullpen once he's activated.