I would sit down with him and ask him why he didn't want to kick the ball or practice.
Ask him in a totally non-aggressive, non-dramatic way. Just tell him you want to talk about something and set him down with you.
Here is what I would do and say if it were one of mine;
Sitting down someplace comfy, no distractions. TV off, Nintendo off, etc... and nobody else around to listen. Just us two.
Me - "So, we need to talk about how come you don't play in the games when its time to. It really bothers me that we let you join the team, and that you didn't play the game or kick the ball. What happened that made you not want to play in the game?"
Give him plenty of time to think and answer. Don't accept "I don't know" or other ways to get out of the conversation - but don't be intimidating. This might be something that embarrasses him too... maybe there's a reason. Maybe there isn't - maybe he just doesn't like it at all and he is scared to tell the truth because he sees how much you want him to like it. Be very gentle.
Me - "I'm talking to you about this because its almost time to start joining teams again, and I want to know how you REALLY feel about it, because I want you to participate in something, but I want it to be something that YOU like and that YOU will play. If you aren't going to play soccer and kick the ball, then I'm not going to sign you up for it."
Let him digest that. See what he says.
Me - "Do we need to choose something else? Maybe we can look online together at things to do around here that you think you'd like better."
If he says he really really really wants to play soccer again - then make it clear that you need a few days to think about it before you say yes, because of the way he acted last season. Explain to him what you expect of him if he does join a sports team - and be sure he understands that.
Maybe you guys are just miscommunicating and opening up the floor for safe, un-punishable conversation is best. That way he can feel comfortable telling you whats going on... AND you can help him get involved in something he'll like.
But thats just me, best of luck to you guys!