Did you rank up either from Spring Training > Regular Season or from Wild Card > Division Series? If you did, difficulty goes up a level for those league shifts - up to All-Star for RS and HOF for DS. I'm guessing the WC > DS jump was the more likely one, so let me know if that was the case. If your PCI suddenly seems significantly smaller, I'd bet on that being the case.
Note that the game defaults to all-star when players in 2 different divisions play each other, so you're not ALWAYS going to be on HOF if you've made it to DS unless you manage your matchmaking setting closely.
And, although it's unrelated to your problem, the devs made HOF the difficulty level for BR until Sunday. So people have probably found it tougher to hit there too.