Was it thrown by a spin bowler? Are there strong winds? Could the throw have taken it to the top of a cliff several hundred feet above the thrower? Must this have occurred on any particular planet? Did the ball encounter something solid in its path, and bounce off it?
Therefore, with the assumption that I made, correct me if I am wrong, the resultant velocity only allows the vector to be perpendicular at the top of the trajectory and never parallel at any point in time and space.