The past: A 41st-round pick by Washington in 2006, the 29-year-old Peacock entered this season with a career record of 11-17, a 4.57 ERA and 4.3 walks per nine innings.
What’s new: Actually, it started last year, when Peacock started taking some velocity off his slider and throwing it more. It has good horizontal run to it, rather than a true power slider with tilt. And while he had an extended run as a starter in 2014 with Houston, Peacock seems better equipped as a reliever. His fastball has a bit more velocity and he can throw his slider more. Check out the change in his use of that slower slider:
April breakout: In 9 2/3 innings Peacock has allowed no runs and one hit while striking out 15.
Sustainability Factor: Medium. His statistics so far are insane. Peacock has a strikeout line reminiscent of Aroldis Chapman's, but he shouldn’t be expected to be that kind of a dominant reliever. But Peacock does appear better suited for relief work than starting, and the change in his slider should keep him effective.