The 3rd argument of pygame.draw.rect has to be a tuple with 4 elements:
pygame.draw.rect(win, (255, 0, 0),(x, y, width, height, vel))
pygame.draw.rect(win, (255, 0, 0),(x, y, width, height))
Alternatively it can be a pygame.Rect object, too:
rect = pygame.Rect(x, y, width, height)
pygame.draw.rect(win, (255, 0, 0), rect)