Can I use a field to change the path in Json Siren?

Question

I'm trying to configure a Siren for my home page but I'm having some trouble with the path. I have a /home that looks like this:

{
  "class": ["home"],
  "properties": {},
  "entities": [
    {
      "class": ["game-list"],
      "rel": ["collection"],
      "href": "/game",
      "title": "List of available games",
      "properties": {
        "games": [
          {
            "name": "Chess",
            "href": "/game/chess"
          },
          {
            "name": "Checkers",
            "href": "/game/chekers"
          },
          {
            "name": "Battleship",
            "href": "/game/battleship"
          }
        ]
      },
    }
  ],
  "actions": [
    {
      "name": "start-game",
      "title": "Start a new game",
      "method": "POST",
      "href": "/game",
      "type": "application/json",
      "fields": [
        { "name": "gameName", "type": "text" }
      ]
    }
  ],
  "links": [
    {
      "rel": ["self"],
      "href": "/"
    },
    {
      "rel": ["login"],
      "href": "/login"
    },
    {
      "rel": ["register"],
      "href": "/register"
    },
    {
      "rel": ["info"],
      "href": "/info"
    }
  ]
} 

How can I change the action so it sends the request to /game/{game} using the gameName in the field to substitute the {game}? Or is there another alternative that I'm not finding?