|A fifth of Kyle|
Gibson's pitches in
2015 were changeups.
As compiled by Baseball Info Systems and published in the Bill James Handbook 2016, here's the percentage of changeups thrown in 2015 as compared to 2014 by five other Twins starters:
Kyle Gibson: 20 percent in 2015, 13 percent in 2014
Trevor May: 19 percent and 16 percent
Tommy Milone: 25 percent and 24 percent
Ricky Nolasco*: 6 percent and 10 percent
Mike Pelfrey*: 14 percent and 9 percent
*Nolasco and Pelfrey don't throw a "changeup" as defined by BIS. They use a splitter instead, and these numbers are for their splitters. Pelfrey's second number is from 2013, since he barely pitched in 2014.
What can we take from this? Pretty clearly there was a greater emphasis with Neil Allen/Paul Molitor on changing speeds than there had been under Rick Anderson/Ron Gardenhire. Milone barely changed, but he was already throwing his changeup almost a quarter of his pitches. Nolasco dropped off pretty sharply throwing his splitter, and I suspect his forearm/elbow issues had something to do with that.
Gibson was obviously a major change, from 13 percent changeups to 20 percent, and it appears to have been a significant pitch for him. BIS says he had the fifth best opposition OPS off his changeup in the American League (.545, rankings based on at least 100 batters faced).