Major league baseball player Stroman's semiautobiographical series starter follows a talented young athlete who learns to handle anxiety on and off the field. It's the summer before middle school, and Marcus--who shares a name with the book's author--is enjoying participating in practice camps for both baseball and basketball until his baseball coach hits the team with an announcement: The players must undergo an "assessment" to earn a spot on the spring team. Meanwhile, though his parents' divorce is amicable--even as they deal with the strict schedules and expenses required for elite athletics--the separation of their households adds even more pressure for a kid already striving for perfection. With his assessment looming, small things find their ways under Marcus' skin more easily, leading his perceptive mom to schedule him a visit with a mental health coach who teaches him to cope with the stress of high expectations. While not everything depicted here happened to Stroman, he shares much with his earnest protagonist, like his determination and uncertainties. The author's note works to destigmatize and normalize mental health care. Practice and game-play details and an entertaining if not particularly deeply developed cast of secondary characters are assets to the pacing. Hints in the text suggest that Marcus, like the author (the son of a Puerto Rican mother and Black father), is biracial. An action-packed, heartfelt story that elucidates the importance of mental health care to young athletes. (Fiction. 8-12) Copyright (c) Kirkus Reviews, used with permission.