Four things that make Rich Hill elite

Rich Hill can still dominate major league hitters, despite any expectation you might have about his age.

How old is Rich Hill? If he appears in a game for the Rays on May 24 or later, he would become the oldest player in club history, besting a record set by Wade Boggs.

Despite having a fastball that averaged 88 miles per hour in 2020, Hill delivered a solid season for the Minnesota Twins. In 38.2 innings of work, he turned in a 3.03 ERA/3.97 FIP. This came after a four year run with the A’s and Dodgers in which he pitched to a dazzling 3.00 ERA/3.51 FIP/3.63 xFIP and a left elbow surgery that repaired a partial tear of his ulnar collateral ligament following the 2019 season.

Now, after reviving his career, Hill finds himself with the Rays on a one year deal, hoping to continue riding the wave of his late-career renaissance.

Hill’s recipe for success is rather simple. He relies mostly on a fourseam fastball and a curveball—one of the best in the entire sport. But Hill’s ability to throw a good curveball is not the only reason he is able to prolong his major league career. Rather, it’s how he has designed it, how he uses it, and how it complements his fastball that make it elite.

1. Spin rate

Ever since spin rate began to be measured in 2015, Hill has ranked among the top pitchers in baseball in spin rate for both his fastball and his curveball. Averaging roughly 2400 RPMs on his fastball throughout this time, Hill ranked in the 79th, 94th, 93rd, 92nd, 91st and 74th percentiles. During the same time, his curveball spin rate, averaging over 2800 RPMs ranked in the 93rd, 94th, 89th, 95th, 95th, and 87th percentile.

This is important because spin affects the trajectory of the baseball. Hitters are more likely to swing underneath a high spin fastball, as the increased spin resists the forces of gravity, causing the illusion of rise. For a curveball, the opposite is true—the increased spin add additional downward force, making hitters more likely to swing overtop of the pitch.

These forces at work are called upward and downward Magnus Effect. Below is a video of this in action:

2. Spin efficiency

It's not just that Hill uses high spin to make the ball move, but there is more to it. What further separates Hill from the pack is that he has both high and efficient spin on both of his pitches. To understand why this is important, we need to understand the two different types of spin.

First, there is gyroscopic spin. For direction of spin, it can be simpler to think about the spin of a football. For a baseball, a pitch thrown with perfect gyroscopic spin means that none of the spin contributes to the movement of the baseball other than the forces of gravity. In other words, there is little to no Magnus Effect. This type of pitch would yield 0% spin efficiency.

Second, there is transverse spin, or the spin that does contribute to movement. The more transverse spin, the higher the spin efficiency. It's the combination of a high spin rate and high spin efficiency that creates the strong Magnus Effect.

On his fastball and curveball, Hill achieved average spin efficiencies (listed as ‘active spin’ on Baseball Savant) of 94% and 100%, respectively. This means that Hill is not only getting movement purely based on the amount of spin, he is maximizing his movement with efficient spin.

Important note: even though terms like ‘spin efficiency,’ ‘active spin,’ and ‘useful spin’ are widely used and accepted terms, their names are a bit problematic. ‘Efficient,’ ‘active,’ and ‘useful,’ imply that higher percentages are good and lower ones are bad. This is not necessarily the case. There are many factors that give pitches their shape.

Using a tool from the site Texas Leaguers, we see how Hill’s pitches interact with the forces of gravity. Here, notice that there is a (0,0) plot. This is where the aforementioned gyroscopic (no Magnus), 0% spin efficiency pitch of the same velocity would land. With this chart, it is much easier to understand the separation of movement between the two pitches as well as how he deceives hitters.

The fastball plot tells us that the pitch has about 11 inches of vertical movement against gravity, also known as ‘rise,’ as well at about 6 inches of armside movement, known as ‘run.’ Compared to the curveball, which has about 7 inches of vertical movement, known as ‘drop’ and about 10 inches of glove side movement, known as ‘cut.’

Put another way, Hill’s curveball moves an extra 7 inches vertically and and 10 inches horizontally than it would had the pitch only moved due to the forces of gravity. This is Magnus Force at work!

3. Tunneling

Let’s revisit the side by side GIF from before. But this time, instead of side by side, the pitchers are overlayed:

Both pitches start with a similar trajectory out of the hand, which adds to their effectiveness.

While Hill has great command of both of his pitches, spotting them well in all areas of the strike zone, he tends to work with his fastball up in the zone and his curveball down in the zone. For hitters, this makes each pitch difficult to tell from one another out of his hand.

When a hitter sees a pitch, they must decide whether they will swing while the ball is in flight. If a pitcher can make their pitchers indistinguishable up until that point, hitters are unable to sit on any one pitch. This concept is called pitch tunneling.

Here is the same overlay from before, but this time, stopped at the point in which the hitter must identify the pitch and decide whether to swing. This is known as the tunnel point:

Up to the tunnel point, it’s hard to tell which one is the fastball and which one is the curveball. While this is not something Hill is particularly known for, we can see how he uses it as another tool in his tool belt.

4. Spin mirroring

This is a lesser known and talked about concept in pitch design, but a very important one for Hill.

In theory, major league hitters are not just great athletes—they also have impeccable vision. Because of this, they can often pick up spin, especially differences in spin axis as well as decipher between two seam and fourseam orientations. What is more difficult to see is whether the ball has back spin (fastball) or topspin (curveball).

With this in mind, now we can understand why this is such an important tool for Hill and his brand of pitching. Not only are these pitches already above average, they have been meticulously worked on and perfected so that hitters have a hard time telling the difference.

Using a new tool on Baseball Savant called ‘spin direction,’ here is a visual of what this looks like.

Hill’s fastball, having efficient backspin, spins towards the red bars, giving the pitch horizontal and vertical movement near the 11:00 direction—his release point. His curveball, spinning the opposite direction, towards the blue bars, gives the pitch vertical and horizontal movement near the 5:00 direction.

Essentially, Hill’s ability to mirror the spin on his fastball and curveball mean they move in nearly exact opposite directions. So the pitches look the same, until they don’t:

Because of all of these things, Rich Hill went from a pitcher who was out of affiliated baseball entirely in the mid 2010’s to being one of the most interesting pitchers in baseball today. For the Rays, he slots into a rotation that is more veteran heavy than years past.

But even as he enters his age 41 season, he can still spin the ball as well as anyone in the game. In fact, his pitches may be as close to perfect as it gets.