The left-hander got the green light to start throwing from Andrews with an eye on participating in spring training.
The 30-year-old starter last pitched on Aug. 13 and missed the final six-and-a-half weeks of the regular season with inflammation in his throwing elbow.
2019 was a disappointing campaign for the seven-time All-Star. In 25 starts, he authored a career-worst 4.40 ERA over 147 1/3 innings, although he managed to maintain a respectable 3.39 FIP and high strikeout numbers (13.3 K/9).
The southpaw is under contract until the end of the 2024 season. He's owed $145 million in salary through that time period and also has a 2025 club option for $20 million.