Here is tonight's Diamondbacks starter (with a 5.53 season ERA) last 5 starts:
CHC - 3.1 IP, 2 ER
NYM - 4.1 IP 6 ER
CHC - 5.2 IP, 1 ER
SD - 3 IP, 6 ER
MIN - 3 IP, 6 ER
Pitchers are literally pausing their slumps to dominate the Cubs and then going right back in them
If you do the math that's a 3.00 ERA against the Cubs and a 15.70 ERA against the other 3 teams.