Darvish posted the recording on his Twitter and Instagram accounts, showing him throwing on flat ground and tagging TMI Sports Medicin, a rehabilitation facility in Texas.
The Japanese star, who signed a six-year, $126 million deal with the Cubs in February, struggled with elbow pain put down to triceps tendinitis from May.
He completed just eight starts before landing on the disabled list. He made two minor-league rehab appearances, one in June and one in August, before he was shut down for the season.
The 32-year-old had arthroscopic debridement of his elbow on September 12.