With Wes Johnson, Twins Pitching Appears to Be Embracing Change

One of the beautiful things about baseball is that history is always being made. During every season, every game, every pitch, we may witness something that has never happened in the long history of this sport.

This offseason, the Twins made baseball history in a different way than I think you were expecting. They hired Wes Johnson, then the University of Arkansas’ pitching coach, to join their big league staff, serving in the same role. According to this story from La Velle E. Neal III in the Star Tribune, Johnson became the first pitching coach in baseball history to move directly from college to the majors. And, at the time, he was believed to be the first coach or manager of any kind to make this transition since Dick Howser left Florida State to manage the Yankees in 1980. That’s some legitimate baseball history there.

What was even more interesting about the Twins’ hire was Johnson’s pedigree as a pitching coach. From Neal’s story:

[Johnson] studies biomechanics. He uses analytics. He is into the gadgets teams invest in to help train pitchers. He earned a reputation in college as a velocity expert, someone who can help pitchers throw harder — although he says it’s difficult to do once a pitcher is no longer in his teens.

Perhaps the story of the Twins hiring a pitching coach who “uses analytics” might not sound all that exciting to you; you likely assume big league coaches use analytics at this point. But the change represented a real organizational philosophy shift.

Now, though, we have some data to work with to evaluate what changes, if any, the Twins have made as a result of the Johnson hire. Of course, any changes discussed here might not be completely dependent on Johnson; other factors such as a change in the arms of the Twins’ pitching staff, their opponents through their first eight games, and even the catcher behind the plate could be impacting the team’s numbers. Still, significant changes could be as a result of a new — or, at a minimum, evolving — club ideology.

With all of that said, it appears that the Twins are subscribing to one of the more prominent baseball-analytic trends: throwing the fastball less often. The idea behind this is simple (if a bit counterintuitive) and Gerrit Cole described it pretty nicely to USA Today last June, saying that due to the increased focus on launch angle, there are “a lot of swings that are dictating breaking balls.”

Can this trend be directly attributed to Johnson? There is some evidence to suggest that a decrease in fastball usage is something that he believes in, but, from what has been written online, it’s not fully clear whether that approach is something that is being adopted staff-wide. For example, according to a story by Do-Hyoung Park at MLB.com, Johnson told Twins reliever Matt Magill to throw his fastball less, instead focusing on a “unique” curveball:

The Twins really like [Magill’s] arsenal, which is predominantly a hard fastball with life and a unique curveball that he throws at a higher velocity than most pitchers. Part of the pitching ideology that [assistant pitching coach Jeremy] Hefner and Johnson have tried to impart upon Magill this offseason has been to push back against the prevailing baseball fixation on fastball usage and command.

If it’s Magill’s curveball that gives him a unique look, why not take advantage of that?

The second prong of Johnson’s philosophy, as a “velocity expert,” is helping pitchers to throw harder. Notably, prior to the season, Johnson worked with 28-year-old Martin Perez to do just that; so far in 2019, he’s seen a 1.9-mph spike on the pitch, bringing him to an average velocity of 94.7 mph.

By no means does the above quote tell us whether Johnson has taken this theory and imparted it to the rest of the Twins’ pitching staff, or if this is just something he found to be specific to Magill’s or Perez’s respective arsenals. Still, the Twins have seen such a significant decrease in their fastball usage that one has to wonder whether Johnson may have played an integral role.

In 2018, Twins pitchers fired a fastball 59.1% of the time. Only four other teams — the Pirates (62.6%), Reds (60.4%), Blue Jays (59.3%), and Cubs (59.1%) — had their pitchers throwing as many or more fastballs. And against said Twins fastballs, batters hit relatively well, posting a .307 wOBA. That ranked 13th in baseball and just slightly above the league-average wOBA (.303) against fastballs.

But this season, the Twins have taken a completely different approach, potentially due to the presence of Johnson in the dugout. Minnesota has dropped its fastball percentage from the 59.1% figure above to just 50.9% so far in 2019; this 8.2-percentage-point drop is the fourth-highest in the major leagues, and the 50.9% overall fastball frequency ranks as the 10th-lowest among all major league teams. If these changes are in fact due to Johnson’s ideology, it’s already making a huge difference in the results. Hitters are having a much tougher time against the fastballs the Twins are throwing, having posted just a .240 wOBA against them this season, good for fourth-lowest in the league.

wOBA, especially this early in the season, can certainly be skewed, but if you looked at these results through xwOBA, which considers batted ball exit velocity and launch angle, the Twins are doing even better. Their team-wide .242 xwOBA against on fastballs is the second-lowest in baseball. Only the Yankees (.236) are better. And, again, this represents an enormous drop. Last season, hitters posted a .316 xwOBA against Twins fastballs, a mark that was 10th-highest in baseball.

It’s still extremely early, but seeing these results through the team-wide lens increases the sample size, even after just eight games. The Twins have already thrown 645 fastballs this year, with 146 batted ball results. Granted, this is still minuscule compared to an entire season, but the fact that these significant changes are happening team-wide suggests that there might be something real to it.

But then sample size, as it often does at this point in the season, comes back to bite us. In the Twins’ first three games this season, their pitchers struck out 39 of the 101 batters that they faced. That represents a crazy-high 38.6% strikeout rate. In the New York Times, Tyler Kepner called this “an encouraging sign for a staff that has struggled for years to master the art of power pitching,” before going into an in-depth look at Johnson’s philosophy.

In fact, those 39 strikeouts were easily (nine more than in 2018) the most strikeouts the Twins have ever recorded in franchise history (since 1908) through three games. But, indeed, strikeouts across the league are up, and this does not account for the variable that all three of these games came against the 2019 Indians, who are quickly establishing themselves as one of the worst hitting teams in the league. Plus, the Twins went on to strike out just 32 of the next 191 hitters they faced, so the jury is still out on whether there will be a real change in Minnesota’s strikeout rate this year.

Still, Kepner’s point about “master[ing] the art of power pitching” still reigns true for at least some Twins pitchers, such as the aforementioned Perez. Across the board, Twins pitchers have seen a 0.2-mph spike in fastball velocity, compared to their 2018 March/April figure (to consider weather as an effect). There might be a lot of noise with this datapoint, but it still ranks in the top-third of teams in increased fastball velocity.

These two facets of Johnson’s belief system — fewer fastballs and harder fastballs — go hand-in-hand. Last June, John Lott of The Athletic explained why a strategy of this sorts works. In throwing fewer fastballs, pitchers are “increasing their use of lower-velocity pitches that move, and making their fastballs better in the process.” The fastball then becomes a weapon, not a given, and helps to keep hitters off-balance.

Changes like the ones that Johnson has made may take more time to show up in the results column, especially for things like strikeout rate and velocity difference. But the early returns, at a minimum, are encouraging. And, in a game that continues to evolve every single day, it’s good to see that Minnesota has begun to embrace the changes that have been so impactful across the rest of the league.