The Back Problem
Full disclosure, I am a huge Los Angeles Dodgers homer, so it pains me to write this article, but it has to be done. Clayton Kershaw won’t be a top 25 starting pitcher in 2019, despite his tenacity, drive, and historical value. Whether people realize it or not, he was not a top 20 pitcher in 2018. Kershaw’s well-known diagnosis of herniated discs that he’s battled for several years and a physiologic phenomenon known as pain inhibition will limit his innings and his production. Here is the simple version.
As medical professionals we tell patients with chronic back problems to avoid repetitive bending, twisting, and lifting. This advice stems from the fact that repeated forward bending, or pitching in Kershaw’s case, often worsens the problem or at least limits the ability of those tissues to heal. Forward bending increases the pressure on the discs, often leading to impingement of the nerves in the low back. Simply put, the more Kershaw pitches, the worse his back problem will get, period.
Yes, this condition can be treated with rehab and surgery, but as a person ages, it is less and less likely that they fully recover. Elite athletes are no exception, and a minor problem is enough to diminish performance significantly.
In 2018, the Dodgers did a masterful job managing Kershaw’s innings to maximize his production without causing too much repetitive stress to his back. I would expect 2019 to be very similar. In fact, I would guess that a phantom injury or a muscle strain of some variety will creep up in June or July. Inevitably this will lead to a 3-4 week stint on the DL to keep Kershaw fresh for the playoffs. This approach is what’s best for Kershaw and the Dodgers.
Pain Inhibition & Why His Velocity is Down
The bigger problem is the body’s protective mechanism medical professionals refer to as pain inhibition. The body knows when it is injured and to avoid further injury the body decreases muscle force production. A perfect example is an athlete who has experienced a torn ACL. Immediately after surgery, the leg feels very heavy and unresponsive. The quadriceps and hamstring muscles are difficult to contract, despite the fact that the ACL is a ligament and not a tissue that contracts. The quadriceps and hamstrings are inhibited to protect the injured knee. After rehab and over time, the muscles wake up and return to ‘normal’ function.
What athletes don’t realize is that returning to 100% takes a long time and if the injury isn’t fully resolved the person may only achieve to 80% or 90% of peak function. We see this problem in a power hitter when they first return from a wrist injury. The X-ray is clean, the athlete feels fine, but the power doesn’t return for a few months (See Justin Turner in 2018). I think we can all agree that at this level of play 80-90% does not cut it.
There is a reason Kershaw’s velocity has declined three years in a row. Age certainly plays a factor, but a chronic back injury will play a more substantial factor than one might guess. In addition to his low back condition and pain inhibition, the mileage on his arm is becoming a problem.
Although Kershaw will only be 31 in 2019, he debuted as a 20-year-old and eclipsed 2,000 innings pitched in 2018. His slider boasted a 16.2 value in ‘18, and the curveball is serviceable at 4.5. His fastball declined for the 3rd year in a row and for the first time in his career registered a negative pitch value, leading to a strikeout rate that dipped below one per inning.
In 2019, the ceiling is 2018 Kershaw, around 160 innings pitched, a high-two/low-three ERA and 150-170 strikeouts. However, the floor for 2019 is similar to what Masahiro Tanaka provided in 2018 – 156 innings pitched with 159 strikeouts, a 3.75 ERA with 1.13 WHIP.