I'm inclined to stay away from this kind of speculation, but in this instance I feel that I have a level of expertise that would allow me to posit a theory that will almost certainly seem like hogwash to some, but I definitely think it's something to consider.
Anyone who has looked at KK last year vs. today and has any experience with the drug would be able to tell you he is in the middle of an Accutane regimen. This is a drug that takes anywhere from 6-10 months to run its course, and it absolutely has the potential to impact one's ability to play a sport, especially at a professional level.
For those who don't know, it is a very intense medication used to treat severe acne, and it temporarily changes your body's physiology in a way that causes no small amount of discomfort—for some this discomfort can be extreme, almost alarming.
I’ve done a 7-month Accutane regimen when I was 22. I’ve always been really lucky with things like soreness, aches, back pain, joint pain, eyesight, etc.
After the second month, I would wake up every day with pain and tightness in my lower back, shoulders, and especially my groin. It would often be uncomfortable to walk; I can only imagine what it would be like to try to skate for a living.
It dries you out. The skin literally falls off your face in flakes. You need to apply moisturizer and Chapstick all day. Some people get hemorrhoids because their you-know-what gets so dry. More importantly in Kaako’s case, it dries out your eyes, causing blurriness of the vision. It makes it hard to drive at night. It makes it hard to see in environments with high levels of brightness, e.g. an ice surface with a bunch of stadium-grade lights reflecting off of it.
Really effective for treating acne though, would do it over 10 times out of 10. The side effects are temporary, but it takes some time. I’d bet dollars over donuts that Kaako is experiencing the kind of Accutane side effects that would impact his play.
Just a theory of course, but anyone who has been through an Accutane regiment can verify the fact that the side effects (soreness, stiffness, dryness) are no joke.