The primary knock against Guerrero is something he can hardly control: He’s only 18, and he does things that 18-year-olds do. Sometimes, during a tedious early afternoon fielding drill, he’ll space out and forget to cover a base or get caught not paying attention as a teammate waits to throw him the ball. Other times, he’ll get annoyed with bad batted-ball luck or hittable pitches he just missed, and carry that frustration into his next plate appearance. If he makes an error at third base early in a game, his coaches can see him thinking about it until the final out. “He’ll make an error and he’ll come back into the dugout very mad. You can see how frustrated he is. I’ll go talk to him and he says, ‘I just want to do everything right,’” Martin says. “And I have to remind him that it’s going to take time. You have to believe in the process. You’re getting better. But everything’s step-by-step. You have to understand that.”

The Blue Jays would like to eliminate the times he carries that frustration through the rest of a game. He’s still a Guerrero, after all, which means there’s no pitch you can throw him that he doesn’t think he can hit. And on the nights when he’s letting his emotions get the better of him, he has a tendency to try to make up for his mistakes with his bat, abandoning his approach and swinging for the fences no matter what the pitcher throws. Sometimes it works, because Guerrero has uncommon power and can hit pitches most players can’t. But expanding the zone and getting over-aggressive aren’t tendencies that will aid productivity as he reaches more advanced levels. “Vlad does get himself out sometimes. He’ll go that extra mile and try to hit the ball too far,” says Lansing hitting coach Donny Murphy. “And he really doesn’t have to. His approach works when he sticks with it. It’s a maturity thing, really. We forget he’s a kid. He’s supposed to be in high school. You know, at his age, sometimes you’re wanting to show everybody how much you’ve got.”