Tracking Jeff Samardzija's development from college wide receiver to big league reliever has been somewhat of a hobby over the past few years. From figuring out what he threw, to the change from slider to curve and, most recently, optimism over the curveball/cutter combo.
I started to see signs of what I would call "progress" earlier this year--in terms of his stuff. His curveball got some depth and he was working on a cutter.
Here you can see which pitch he was throwing over time. Barely any overlap.
Now the Shark hunt brings us full circle. His cutter has slowly become slower. Barely a cutter and more of a slutter from the get-go, it now quacks like a slider, walks like a slider and should just be called a slider.
These three graphs compare each of his three pitches to his fastballs from the same game. With one exception, the fastballs are four-seamers (click the image to enlarge). The timelines have been shifted so it's Day 0 for each pitch on the left. As shown above, they didn't actually overlap like this.
The speed and movement relationships between his sliders and fastballs of old look no different than those of his cutter and fastball of new. The gradual change in the cutter is interesting, as it began slowing down and sinking more, as opposed to the "new pitch" events that can be pinpointed in the past.
Now we've got a guy who rarely throws a sinker (despite early season flashes of it), has settled on a splitter for his offspeed pitch, and has gone full circle with the breaking pitch.
Finally, we can say Samardzija is a reliever with a fastball/slider/splitter instead of saying he is the Cubs' best third down option. Which is still true.