I don't want to get trapped in the friend zone.

[Genersis]

There's nothing you can really do except make clear you're interested and give him space and time(the "Fourth Dimension" approach, if you will...sorry, that was an awful joke...).

Also, don't expect him to choose to be with you once he is ready for a relationship.
Keep your options open, don't go out of your way to wait for him(I hope that makes sense).