Kwang-Hyun Kim provided the Cardinals with some much needed stability in the Cardinals pitching staff which saw ten different pitchers start a game in a season where the Cardinals played just 58 games. Kim started seven games, tallied a save, and threw the third most innings for the team behind Adam Wainwright and Jack Flaherty. However, even though Kim had a solid season in terms of run prevention (1.62 ERA), he also struggled to miss bats and benefited from an 86.6% left on base rate and a .217 BABIP. This casts doubts on his outlook for the next season which is the last of his 2-year, $8 million contract.
It is difficult to judge a pitcher who has thrown just 39 career MLB innings. However, Kim kept a similar profile in the MLB as he did in the KBO. He is a pitcher who does not walk many batters (2.77 BB/9) or allow many home runs (0.69 HR/9), but he also does not strike out many hitters (5.54 K/9). However, even for a control artist, this is a low strike out rate. Additionally, Kim was in the bottom 4% of the league with his whiff rate. It makes sense that he struggled to miss bats as his fastball average just below 90 mph, and his two breaking balls (slider, curveball), as well as his fastball, had below average spin rates. This makes Kim very dependent on contact results. His low walk rate prevents him from hurting himself, but he is also very reliant on the hitter being unable to hit the ball hard. This can be a dangerous game for a pitcher to play, and if he is going to pitch this way then he must be able to locate his pitches very well.
The good news for Kim and the Cardinals is that Kim does locate his pitches well.
According to Baseball Savant, Kim lives in the bottom of the zone as he threw 36 percent of all his pitches in the bottom two zones. These zones encompass the edges of the bottom half of the strike zone and the surrounding areas outside the zone. This is a good spot for Kim to locate his pitches, given his lack of velocity and elite spin rate and it likely helped him limit the amount of hard contact that he gave up. Kim threw 45.5% of his pitches on the edge of the strike zone which is a good amount higher than the league average of 39%. His ability to keep the ball down in the zone and on the edges of the zone likely contributed to his solid barrel rate of just 4.2% as well as his 87.1 mph average exit velocity allowed, which is 1.2 mph better than average. Additionally, Kim does a very good job of generating groundballs (50% GB%) which helps minimize the damage that he allows even more, as the little hard contact that he allows has an even smaller chance of leaving the yard. His 31.4% hard contact rate puts him in the top 16% of MLB pitchers and that has played a large role in his ability to prevent runs despite being incapable of missing bats on a consistent basis.
Kim has surely benefited from a low BABIP that does not matchup with his career numbers in the KBO as well as a high left on base rate. However, he does appear to be capable of somewhat controlling the type of contact that is made by hitters. He does this by locating just 27% of his pitches over the middle row and middle column of the plate, while keeping everything else on the edges of the strike zone or outside of it. Even without an intimidating arsenal, this allows him to minimize hard contact. It is a dangerous game to play, and it could backfire whenever he loses his command. Additionally, with such a small sample size, it is possible that he was lucky with his results allowed on contact. This means that it is unlikely that he ever comes close to repeating his ERA this season. His FIP (3.88) and xFIP (4.52) tell a much better story of who he is as a pitcher. SInce he is 32 years old, benefited from a good amount of luck, and has an underwhelming arsenal, it is difficult to feel like Kim is a game changer for the Cardinals pitching staff. However, if he can keep his strong command and keep the ball on the ground, he could be a capable back-end starter for the Redbirds in 2021.