A 28-year-old right-hander, Knebel hurt his elbow during spring training and had surgery on April 3. He had been eligible for salary arbitration and will have the same salary as in 2019.
His deal includes a $50,000 bonus for being comeback player of the year along with other award bonuses.
Knebel had 39 saves in 2017, when he was an All-Star, and 16 the following season.
His deal was announced Tuesday.