Basketballs are full, symmetrical and resilient- all of which could represent your personality- perhaps you feel you've fulfilled what you want to, your life is balanced and you have built a healthy attitude towards any negativity that comes your way.
With that said, if the basketball was punctured or slashed, someone or something threatens to harm this equilibirum. Consider who else was in the dream with you for additional insights.
When you dream about basketball, it can be about both teamwork and cooperation. Perhaps you are in a situation in your waking life that demands help from others in order for it to work. You may be struggling on your own so it might be time to ask for assistance.
It can also be a reminder that you need to focus on your goals if you have lost sight of them lately.
It's possible you need to make the first move when it comes to a situation in your waking life- if you have been reluctant- now might be the time to take action.
To dream about playing basketball against another side, as part of a team, it's possible you have some conflict in your waking hours that needs to be resolved.
If you lost a game- it's possible you think you've missed out on something at work or in your personal life. Will the opportunity present itself again? If so, don't feel too defeated- there is always next time.
If you were bouncing a ball on your own- you may be trying to work something out and it could be the right time to make a decision.
To be a spectator of a basketball game may indicate your shyness or self-consciousness that is having an impact on you reaching your goals. What can you do to give your confidence a boost? Or it could represent an avoidance of risk and an uneasiness around those who are willingly take them. Try to separate yourself from these people if you think it's going to end up in tears, however if in comparing yourself, you have revealed something you need to work on, use it as a motivator.