If I donate blood can I play soccer the next day?

Ask Donation Center. Ask the donation center staff if they have a list of precautions you should take after blood donation. If you have a significant competition, do not donate blood within 7 – 10 days of the event, as your performance will be compromised. A recent study (in omega cycling) found maximal performance was decreased for at least 1 week and that submaximal performance was unaffected by blood donation.
You can't play well. Aerobic exercise increases plasma volume. This enhances left ventricular filling pressure, which increases contractility and cardiac output. By donating blood you are negating an adaptive response that can enhance playing an aerobic sports. You play, but not as well.