Michael Kopech's personal trainer thinks he can throw 107 mph

Move aside, Aroldis Chapman: There's a new sheriff in town.

Chicago White Sox prospect Michael Kopech, whose fastball touched 105 mph in a Class-A start last year, was part of the deal that sent Chris Sale to the Boston Red Sox. Kopech's personal trainer thinks his client's arm can eventually revolutionize the sport.

"I feel like this is a kid who can change the game," said Bobby Stroupe, according to Bleacher Report's Scott Miller. "I think he's going to throw 107 mph. I really do. And not just once or twice a month."

The 20-year-old said the key to building his velocity was relaxing after he finally achieved his goal of throwing a 100-mph pitch - a week before he turned 19.

"I stopped caring about how hard I threw," Kopech said. "I hit 100, so I can throw 100. I started worrying more about how I was pitching. After that, the velocity just came. It was easy. Sometimes I'd be in the sixth inning throwing 100. It was pretty easy for me after that."

Kopech enters 2017 as baseball's 16th-best prospect, according to MLB Pipeline, and he's held in high regard by ESPN's Keith Law, who rated him as the game's best pitching prospect.

He's also had some early brushes with controversy: He was suspended 50 games for use of a banned stimulant and broke his hand in an altercation with a teammate last season.

Kopech isn't expected to be part of the South Siders' plans until 2018 at the earliest.