In my experience, once the leaf starts to yellow, that is a gonner. Especially at the bottom of the leaf. If it was starting at the top, you could cut The yellow part off.....The stem may still be ok. I've had single stems grow new leaves.

I agree that if a leaf starts to spontaneously yellow at the base it's probably a gonner---but this leaf looks like its yellowing in response to some sort of damage (or "boo-boo" as the professionals say) so I wouldn't give up on it yet...best case scenario-- just sun damage (or some minor injury from being outside), cutting roots easily...fingers crossed....keep us posted....

It could have gotten some sun damage from brief periods of sun on its shelf. That shelf gets very little, if any, sun, so I thought it was safe. But I'll wait for now and see what happens. Thank you, and I will keep you posted.

Half the bottom is still green it has a fighting chance

I suspect the stem has died, when yellowed just off the stem like that. I had a similar piece myself last week which I tossed. The yellowing leaf came off the stem w/ a gentle tug & I realized the stem was shot. Another gentle tug & the stem came out of the mix easily, showing me it was losing its roots.

Sure you can try, but I wouldn't get my hopes up.

I tugged gently on the leaf, and it stayed put. I tugged the stem too, and it definitely didn't budge, so maybe it still has sufficient roots.

I'd just leave it. Barring further progression of the yellowing, or signs of rot, it should be okay. Since it seems to be well-rooted, it should put out new growth, soon. Once the first few leaves have matured, if it hasn't fallen off on it's own, you may remove the ugly leaf, if you desire.

Yes, I'm just leaving it alone and not watering until it's completely dry. Good light, no direct sun. I'll hold my breath and hope I get new growth!