Jun-Seok Shim’s debut was short-lived. The Pirates’ top international signing from last off-season, Shim only pitched eight innings in four outings for the Pirates’ Dominican Summer League affiliate. He looked decent when he pitched, striking out 13 and allowing three walks with only one home run, but I personally really wish he had stayed healthy to pitch more.
There's a reason why Shim is so highly touted. The South Korean right-hander opted to take his talents to the United States but was considered the best pitching prospect in South Korea, had he entered the KBO draft. Shim, who was only 18 at the time he signed, was topping out in the triple-digits and was regularly sitting in the mid-upper-90s with his fastball.
Shim's best secondary offering is his curveball with 12-6 shape. It also has plus potential, but as FanGraphs notes, it is easy to read out of the hand. Shim also throws a slider and change-up. Even though they're further behind than his fastball and curveball, they do project as average pitches.
But Shim isn't just a hard thrower with no control. He has displayed control that is developed much further along than many of his age with his powerful stuff. Shim has a repeatable delivery and good athleticism, which could help him improve his command even more. At the very least, he could have fringe-average control over his stuff.