KANSAS CITY -- Royals right-hander Ian Kennedy appeared to be headed for a career year in 2017, posting a 2.30 ERA through the first month of the season, as opponents slugged just .262 against him in April.
But in early May, Kennedy suffered a right hamstring strain, and his season was never the same.
Kennedy finished the year with a 5.38 ERA, his worst since 2008. And the righty believes he knows why: After coming back in late May, his hamstring injury never fully healed, and it robbed him of perhaps his most effective pitch, his changeup.
"[The injury] was tough," Kennedy said. "I felt like it took away my changeup, which I didn't have until my last start of the year. Every time I threw the changeup after I came back from the disabled list, I could feel [the hamstring]. It was just on the changeup. It got worse and worse."
The numbers back up Kennedy's observation. Before the hamstring injury, opponents hit .100 off his changeup (2-for-20), slugged at .250 and had a whiff rate of 48.7 percent, per Statcast™. But after the injury, opponents slugged .429 off his changeup and his whiff rate dropped to 27.4 percent.

Overall, after returning from the injury on May 21, Kennedy's ERA soared to 6.08 and teams slugged .528 against him. He simply wasn't the same pitcher.
"[The hamstring] wasn't feeling great at the end of the season," Kennedy said. "It wasn't hurt. It just felt more tired, so I wasn't using that leg as much and I think I was compensating in other ways. It just wasn't working."
Kennedy recently began his offseason workout program, and his No. 1 goal is to ensure his hamstring issues will be a thing of the past.
"I've been working out and trying to incorporate more stretching, some Pilates a little bit, just to get more flexibility," Kennedy said. "I'm tired of having problems with my hamstrings. I'm exploring a bunch of ways to make sure it's not going to be a problem again."