We learned yesterday that Lakers forward/center Moe Wagner would be missing all of the preseason due to the “lateral left knee contusion” that kept him out for most of Las Vegas Summer League.

I can hear you saying ‘hold up, you’re telling me a bruised knee has kept him out for this long?’ and I’m here to say yeah, and here’s why.

“Knee contusion” is often used as a code word for a “bone bruise.” Whenever a player misses an extended duration with a “knee contusion” or the player is diagnosed after imaging, it’s almost certainly a bone bruise. For example, when Lonzo missed the last eight games of last season with a “lateral knee contusion,” it was almost certainly a bone bruise (he later was additionally diagnosed with a torn meniscus).

Another example is Andre Iguodala, who was diagnosed with a “lateral knee contusion” after Harden ran into his knee during the Western Conference Finals, but missed the next six games. During his absence, he and numerous others straight up referred to the injury as a bone bruise.

The reason why medical staffs don’t just come out and say “bone bruise” is because that term is a colloquialism rather than a medical term, and teams tend to be as nondescript as possible with injuries anyways.

If we apply the duration and imaging indicators to Wagner’s case, his knee contusion is almost certainly a bone bruise. He’s already missed over two months (over three months by the time pre-season ends), and was officially diagnosed after an MRI.

The reason why MRI is used for the diagnosis speaks to the difference between a superficial bruise and a bone bruise. Unlike the former — which is just broken blood vessels — a bone bruise actually involves a microfracture of the bone, which is one step in severity below an actual fracture. Technically, it’s called a microtrabecular fracture.

Here’s a visual:

There are multiple types of bone bruise but I’ll save you the horror. Regardless of type, they can be notoriously painful and linger for a while.

I’ve had one — if you’re on a bicycle, keep your head on a swivel at a four-way stop — and it thoroughly sucks because bone is densely innervated with nerve endings resulting in a lot of pain, swelling can travel from the bone to the muscles around it (in Mo’s case, the quads, calf, hamstrings, etc) which means more pain and limited function, and two nerves, the common peroneal and lateral sural nerve, are near the knee’s surface and prone to irritation.

It’s somewhat common for either of these nerves to become irritated after a lateral bone bruise and cause additional symptoms like tingling, numbness, feelings of “tightness,” etc.

For all these reasons, a bone bruise can linger for weeks to multiple months. You add in how conservative the Lakers training staff is with their less physically developed younger players (a zero pain return to play protocol, as we’ve seen during Lonzo’s various rehabs), plus the fact that Wagner isn’t an integral part of the rotation right now, and you have a recipe for him being held out for a significant amount of time.

It’s for these reasons that his timeline and being held out of pre-season isn’t a surprise to me. I’m just glad his vocal chords aren’t affected so that he can at least yell from the bench.