Too bad this was on the radio. It sure would’ve been great theater seeing the startled look on Suzyn (Ma Pinstripe) Waldman’s face Sunday when John (Pa Pinstripe) Sterling decided to give the free world his take on the most recent steroids caper, which allegedly involves Alex Rodriguez. This is the same Sterling who often is heard as Rodriguez’s yard barker, his cheerleader-in-chief with the “It’s an A-bomb by A-Rod” HR call. Sterling’s chemical interlude during the Blue Jay’s-Yankees exhibition, WCBS-AM’s first radiocast of the season, didn’t have the nuclear capabilities of an old A-Rod blast, but provided a significant jolt. More pop than what came out of the Yankees Entertainment & Sports Network booth, which took a more conservative approach Sunday when reporting the A-Rod story during its first telecast of the season. Baseball on the radio is relaxing. Exhibition baseball on the radio is sleep-inducing. Yet, to his credit, Sterling not only provided a wake-up call, he caused serious whiplash. Sterling was under no internal pressure to address this topic. There’s no doubt Yankee brass would rather Pa forget it— kind of like he does with balls and strikes. Did Waldman’s head snap back when Sterling segued from straight play-by-play . . . “and the pitch is” . . . to the Miami wellness clinic and biochemist Anthony Bosch? “But they (MLB officials) have to prove all this,” Sterling said. “It’s got to be proven.”