The middle-size league soccer competition is an important RoboCup event designed to promote advancements in Artificial Intelligence (AI) and robotics. In recent years, soccer robots using a dribbling mechanism, through which the ball is controlled using two driving rollers, have been adopted by teams worldwide. A survey conducted during the 2017 World Cup in Nagoya revealed that the teams determined their roller arrangements heuristically without the use of a formal mathematical process. In this study, we focus on sphere slip speed to develop a mathematical model for sphere rotational motion, allowing for slip. Using this framework, we derived the relationship between the sphere slip and mobile speeds and evaluated the roller arrangements used by the participating teams.