Duke was acquired at the trade deadline to add some bullpen depth for the Cardinals’ stretch run, and posted a 1.93 ERA and 2.00 K/BB ratio in 23 1/3 innings for the club. He stands to make $5.5 million in 2017, the last vestige of a three-year contract that he signed with the White Sox in the 2014 offseason.
Prior to undergoing Tommy John surgery, as well as getting his flexor muscle repaired, the left-hander had no prior known history of major injuries. His closest brush with a long-term setback came in 2007, when he landed on the 60-day disabled list with minor irritation in his left ulnar collateral ligament.
The Cardinals still have three lefties in their bullpen with Kevin Siegrist, Dean Kiekhefer, and an injured Tyler Lyons. Possible internal replacements for Duke include left-handers Marco Gonzales and Tim Cooney, though with both pitchers sidelined with shoulder and elbow injures, the Cardinals are also expected to peruse the trade market as the 2017 season nears.