1) So you want to say it without saying it?
Leave doubt in the kid's mind as to where he stands?
A lack of communication leads to nothing good.
2) Alternatively you can tell him he has been dropped for a soft effort so that he dwells on it for weeks until he gets back into the side to redeem himself?
This is not how you build confidence and BELIEF.
3) Or failing that, you can drop him and specifically tell him that it is NOT because of him hearing footsteps.
Then the kid is still down, questions and doubts himself and whether the football dept is being honest with him.
4) The answer is to maintain faith in him that he will redeem himself and give him the soonest chance possible to show that.
If it becomes a worrying trend, then maybe you take a different tact.
No good can come from the other options.
Such a simple concept, but so hard for some to understand...