Alex Speier: “When Brayan Bello takes the mound Wednesday, he will do so as the most anticipated Red Sox pitching prospect in years. Not since Eduardo Rodriguez in 2015 has a Red Sox minor league pitcher arrived in the big leagues with as clear a path to being a rotation anchor. That Bello occupies that space almost exactly five years after signing with the Red Sox represents a remarkable development. He was a passed-over prospect on the international market who was overlooked by all 30 organizations for his first two full years of eligibility to sign. When the Red Sox finally inked him as an 18-year-old July 2, 2017, he signed for less than $30,000. “I just took it as a challenge knowing that I wasn’t ready at [16] to sign and play professional baseball,” Bello said recently. “I took that year and a half to get more strength in my body and perform the right way so the chance eventually would come.”