GLENDALE, Ariz. - A solid 6-foot, 215 pounds, Julio Urias does not look fragile. Not walking around a big-league clubhouse and certainly not on a pitcher's mound.But history says he is."I think the data is very clear that if you're throwing too many innings before the age of 24, it dramatically decreases the likelihood of you throwing a lot of innings after the age of 30," said Urias' agent, Scott Boras, whose staff has done extensive research on the topic.