No matter how young they are, they're still umpires, and therefore the target of shouting from players, coaches and parents.
Yet they're still willing to take on the big job.
According to Baseball Ontario, there are more than 2,700 certified umpires under 18 in the province, including nearly 130 girls. They umpire a couple of games every week for about $20 an outing.
"You have some people right behind home plate saying, 'That was a bad call' or 'That should have been a strike,'" says umpire Ryan Railey, 16.
"I sort of block it out and don't listen to it 'cause I'm calling the game. That's how I deal with it."
Umpire Marisa Sproxton, 13, has also had an unpleasant experience.
"I don't know if he was a parent or grandparent. He was yelling from the stands at the players, at the coaches, at me, at everybody," she recalls.
A smoking heckler
"I asked him if he could stop, and he said, 'I'll do what I want' and then he moved his chair to behind me," she says.
"He was smoking and it was going to the kids' faces. I was very close to asking him to leave because he was really bothering the kids."
While teens like Ryan and Marisa stick it out, many tire of the catcalls, insults and taunting, and they quit.
Developing a thick skin comes with experience, says Alain Fournier, past president of Little Britain Baseball north of Oshawa, Ont.
"It's hard for some (kids) to say 'Excuse me, m'am, can you keep it down?' or 'Coach, I'm right,'" Fournier says.
"Sometimes there's a little growing up that they do real quickly in an umpire role."
Baseball Ontario runs clinics to help young umpires grow into their roles.
Absorbing criticism is part of the umpire's job, regardless of his or her age, says instructor Jamie Graham.
"When I started as a younger umpire, it bothered me," he says.
"Eventually you just learn to compartmentalize it. It might just mean that 35-year-old dad is living vicariously through his son, and I'm not going to let him bother me."
Marisa, in her second year as a umpire, developed a thicker skin shortly after her heckling incident.
"You can't really quit after one person being like that," she says.
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