The phrase "a small possibility of" is correct and usable in written English.
It can be used when discussing the likelihood or chance of something occurring, particularly when that likelihood is low.
Example: "There is a small possibility of rain tomorrow, so you might want to bring an umbrella just in case."
Alternatives: "a slight chance of" or "a minor likelihood of".
No one has been dropped and there is only a small possibility of any change to the final XI.
But in quantum mechanics, there is a small possibility of "tunneling" through the bump, and finding the new, lower energy region.
The swamping principle also applies to a small possibility of an enormous evil, which can provide a good reason for not acting.
For safety, it was necessary that any circuitry hooked up to a user's head had absolutely no path to a power outlet in order to eliminate even a small possibility of an electrical surge to the head.
The risks were substantial: hair loss, diarrhea, infections, a small possibility of permanent numbness that would leave her hands feeling as if she were wearing leather gloves, yet exquisitely sensitive to cold.
My analysis places much lower weight on a future dollar than a dollar now, for the ethical reasons that future generations may have higher consumption and that there is a (small) possibility of extinction, for example from a meteorite.
Robinson speculates that there is a "solid possibility of finding fossil traces of life and a smaller possibility of finding existing life, under the surface" of Mars.
I think there's a small possibility that some of it has been given to terrorist groups, but I'm willing to believe that it was there.
There would be only a very small possibility of one seed falling to the soil and becoming a GM weed.
But weakness remains a bigger worry than an overheated economy because of the small possibility of an "unwelcome substantial fall in inflation," the Fed said, not using the word deflation.
