Aaron Sanchez, Toronto Blue Jays
ERA through April 30th: 2.32
ERA since May 1st: 5.71
This certainly wasn’t a surprise, especially since we named Sanchez as one of baseball’s worst starting pitchers through the end of April. That was because his 2.32 ERA was accompanied by a 5.45 SIERA, and it looks as if regression came quickly for the right-hander.
His last 41 innings have included six losses in eight starts (and no wins), along with a 17.7% strikeout rate, 10.4% walk rate, and 5.04 SIERA. It’s also worth noting that his BABIP allowed has jumped over 100 points (.241 in April, .344 since May 1st). This has all happened despite raising his ground-ball rate (48.1% to 52.2%) and his soft-hit rate (14.8% to 23.1%).
Entering this year, Sanchez had never thrown his curveball more than 16.6% of the time, but that number is currently up at 23.1%. The results have been stellar; plate appearances ending with that pitch have produced a 4.2% walk rate, 40.3% strikeout rate, and a 26 wRC+. The problem is his four-seamer and sinker — both pitches have produced a walk rate above 13.0% with at least a 160 wRC+ against.