DH and I are not interested in football at all, but we’ve been sending DS (4.5) to Saturday football for about a year now. I think it teaches great skills - teamwork, following instructions, being active, social skills, and will mean he’s able to join in in the playground later if he wants to.
He’s naturally quite a reserved boy but this is really bringing him out of his shell. Any team sport would be just as good, but football is the most accessible where we are.