Farquhar (head) was outrighted to Triple-A Charlotte on Friday and will become a free agent following the conclusion of the 2018 season.
Farquhar appeared in eight games for the White Sox this year but had his season cut short when he collapsed in the dugout due to a brain hemorrhage in late April. The 31-year-old spent a couple weeks at a hospital and was ruled out for the remainder of the year. His timetable for getting back on the mound is unclear, though he's expected to try and make a comeback for the 2019 campaign.