With pitching obvious trade-deadline focus, are Cubs getting best version of David Peterson at right time?

ST. LOUIS – When David Peterson served up a solo homer in the second inning Monday night, it looked like a continuation of a potentially worrisome trend. The Cubs’ lefty starter arrived in a midseason trade with a reputation as an elite ground-ball pitcher, and given the Gold Glove defenders populating the infield, it seemed like a perfect fit, the right ingredients for a change-of-scenery success story after Peterson, a 2025 All Star, saw his fortunes dip with the Mets. But since coming to the…