Sunday was Porter's first plate no-hitter, the first MLB no-hitter since September 1 2014 (Jordan Baker 1; Hamels, Diekman, Giles, Papelbon) and the first single-pitcher no-hitter since June 25, 2014 (Adam Hamari 1; Tim Lincecum). Crewmate Gary Cederstrom has also called a no-hitter (June 1, 2012; Johan Santana).
Porter received 39 callable pitches, a total of 25 balls and 14 called strikes; the look:
Balls: 25 called balls outside of strike zone / 0 called balls within strike zone = 25/25 = 100% Accuracy.
Strikes: 13 called strikes inside strike zone / 1 called strike outside strike zone = 13/14 = 92.9% Accuracy.
Total Raw Accuracy Score = 38/39 = 97.4% Accuracy (+1 For Zimmermann).
In other words, Porter came within one pitch of calling a perfect game for Zimmermann's no-no.