As batting practice was about to begin, Craig Biggio found himself in an unfamiliar baseball setting: standing behind a velvet rope that kept special guests of the Blue Jays from running onto the field and getting in the players’ way.



Biggio was not just any special guest, and he certainly could not embarrass himself on a baseball field. He’d spent 20 years in the major leagues, all with the Houston Astros, and in 2015 he was elected to the Hall of Fame. He was known as the consummate pro.



But on this day, more than all of that, he was a proud parent.



A day earlier, Craig and his wife, Patty, were in New Jersey, preparing for a weekend trip to Allentown, Pa., where the Buffalo Bisons would open a series against the Lehigh Valley IronPigs on Friday night. The Biggios’ middle child, Cavan, was a prospect of note for Buffalo, the Blue Jays’ top farm club. They would spend the U.S. Memorial Day weekend immersed in baseball and family...