Have you noticed the Cardinals’ sudden surge in the second half of the season? They’ve broken the original three-way dominance in the NL Central, claiming the top spot and leaving the Cubs and Brewers, the two major powers in the division, behind. Although the Cardinals’ lead isn’t huge and there’s still about a month left until the playoffs, according to data from FanGraphs, the Cardinals’ chances of winning the division title experienced a “death cross” by the end of August. The Cubs, who had been far ahead in championship probability, were dramatically overtaken by the red-hot Cardinals in August.

Let’s take a look at the performance of the three teams in the NL Central that were originally neck-and-neck, after the All-Star break:

Team W-L Win %
Cardinals 34-16 0.680
Cubs 28-20 0.583
Brewers 24-23 0.511

Given such a difference in records, it’s not hard to imagine why the Cardinals surged so quickly. Assuming the Cardinals maintain the same high winning percentage until the end of the season, they would finish with 94 wins. Currently, the Cubs, in second place in the Central, would need to go 20-4 to surpass the Cardinals by the end of the season. Of course, it’s unlikely the Cardinals will maintain this red-hot streak indefinitely, and before the season ends, the Cardinals and Cubs still have 7 games to play against each other. Undoubtedly, the outcome will still be highly variable, but there’s no denying that the Cardinals have played exceptionally well during this period, and one of the key figures in this success is none other than Jack Flaherty.

Jack Flaherty was already a pretty good pitcher. While he wasn’t much of a strikeout pitcher in the minors, he showcased excellent strikeout ability upon reaching the majors. Last year was his first full season in the big leagues. In 151 innings pitched, he recorded 182 strikeouts with an ERA of just 3.34, which is a very respectable performance. Had Miles Mikolas not pitched so exceptionally well last year, Flaherty would likely have been the Cardinals’ ace at the start of this season. Even though Flaherty was already an above-average pitcher, his rapid improvement in the second half of the season has certainly been a major surprise for the Cardinals.

 

<table><tbody><tr><td> </td><td>Games</td><td>ERA</td><td>WHIP</td><td>Opp. AVG</td></tr><tr><td>Pre-All-Star</td><td>18</td><td>4.64</td><td>1.23</td><td>0.237</td></tr><tr><td>Post-All-Star</td><td>10</td><td>0.85</td><td>0.76</td><td>0.147</td></tr></tbody></table>

After the All-Star break, Jack Flaherty’s ERA ranked first in all of MLB. His WHIP was second only to Justin Verlander, who had just thrown a no-hitter, and Ryan Yarbrough, the Rays’ ‘opener’ who was promoted to a starter role. In these 10 starts, he earned 5 wins for the Cardinals, and his WAR during this period was 2.6, ranking second among all MLB pitchers. Such an outstanding performance also earned him the National League Pitcher of the Month award for August.

I noticed a significant change in Jack Flaherty’s pitching mechanics before and after the All-Star break. Originally, with no runners on base, Jack Flaherty would take a small step back and forth with his right foot before striding forward with his left. Now, he has eliminated this step, and his pitching motion has become simpler.

Jack Flaherty’s Rocking Motion Pre-All-Star Break

Simpler Pitching Motion Post-All-Star Break

Furthermore, with runners on base, after the All-Star break, Flaherty positions his glove closer to his head during his wind-up, and his upper body adopts a slightly bent posture, giving the impression that his upper body’s center of gravity is lower.

Pre-All-Star Break

Post-All-Star Break

Jack Flaherty’s changes can also be seen in his release point. Starting around July, the release point for all his pitches has become progressively higher:

So, what benefits might these pitching mechanic adjustments have brought to Jack Flaherty?

Most notably, Flaherty’s home run rate has significantly decreased. Home runs were Jack Flaherty’s biggest issue before the All-Star break. He was giving up an average of 1.86 home runs per 9 innings. After the All-Star break, this figure dropped to just 0.43, which is the best in all of MLB. Paradoxically, Flaherty’s fly ball rate actually increased in the second half of the season. This suggests he started inducing more weak fly balls from hitters.

Flaherty also has another astonishing record in the second half of the season: Since August, none of the 82 sinkers he has thrown have resulted in a hit. We can also clearly see the change in his sinker’s pitch location before and after the All-Star break:

Sinker Pitch Locations

Before the All-Star break, a significant portion of Flaherty’s sinkers were located high and outside the strike zone. After the All-Star break, his sinkers were concentrated at the lower edge of the strike zone.

While Jack Flaherty’s performance has been red-hot, it’s worth noting that Jack Flaherty’s BABIP in the second half of the season is exceptionally low at 0.212 (A low pitcher BABIP often indicates good luck for the pitcher; for a more in-depth discussion on BABIP, please refer to my other article: Is Top Prospect Fernando Tatis Jr.’s Great Performance Just a Flash in the Pan?). This makes me somewhat concerned that Flaherty’s future performance might decline.

The good news is that Flaherty’s average exit velocity against him has noticeably decreased in the second half, dropping from 87.3 mph to 85.4 mph. Furthermore, his line drive rate allowed has significantly decreased compared to the first half. Data from MLB Baseball Savant also shows that Jack Flaherty’s expected weighted on-base average (xwOBA) was 0.317 in the first half, but it has dropped to just 0.232 in the second half. This indicates that it’s not just luck; rather, hitters are genuinely struggling to make solid contact with the ball.

Conclusion

Whether Jack Flaherty’s surprising second-half performance can continue until the end of the season will be a crucial factor in whether the Cardinals make the playoffs. Currently, it appears that his adjusted pitching mechanics are indeed effective in suppressing hitters. However, the unusually low BABIP also hints at some underlying concerns. Let’s continue to follow the future performance of this young talent!

Data Sources:

MLB Baseball Savant, FanGraphs, Baseball Reference, BrooksBaseball,

Ben Godar. Here’s all the ways the Cardinals can win the division. https://www.vivaelbirdos.com/2019/9/4/20849223/heres-all-the-ways-the-cardinals-can-win-the-division

GIF and Pitching Motion Image Sources:

MLB Baseball Savant

Cover Image Source:

MLB Cardinals Official Website PC: Jeff Roberson/AP