Pitching as both a reliever and starter in 2016, Duffy finished the year 12-3 with a 3.51 ERA and 188 strikeouts in 179.2 innings pitched. The Royals rewarded the left-hander with a five-year extension worth $65 million.
While Duffy has performed well on the mound, durability has been a concern for much of his MLB career.
He underwent Tommy John surgery in June 2012, which left him out for much of the 2012 and 2013 seasons. Since then, he has suffered minor problems, such as a rib-cage injury in 2014 and biceps tendonitis in 2015.
Any worries about Duffy's health are more heightened now not only because of his new contract but also the fact he's the Royals' ace. Kansas City doesn't have one of MLB's worst starting rotations, but the team's starters as a collective unit are arguably in the bottom half of the league.
Duffy's injury is a major blow to the Royals, who are already last in the American League Central with a 21-28 record.