Pivetta's hot start can be traced to a number of improvements in his curveball, The Athletic Philadelphia reports.
The curve has improved in just about every way possible. It's now dropping by 10 inches after dropping just 5.7 inches last year. Its horizontal movement is up from 3.3 inches to 6.3 inches. Pivetta's now throwing it at 80 mph after it averaged 77 mph in the first half of 2017. The changes stem from a change in grip after he decided to copy the spiked grip used by teammate Aaron Nola. Pivetta has also quieted his hands during his windup, which has helped not just the curve but also his overall command, and he's now walking just 3.6 percent of the batters he faces. Pivetta's 2.57 ERA seems at first glance easy to dismiss as a small-sample fluke after his 6.02 ERA last year, but changes in the curve seem to be driving a legitimately improved performance from the young righty, and his 2.28 FIP backs up the idea that he's deserved his excellent results.