Evaluation of creating scoring opportunities for teammates in soccer via trajectory prediction
This work addresses the challenge of assessing attacking players without the ball in soccer, which is important for teamwork evaluation, scouting, and fan engagement, though it is incremental in applying trajectory prediction to a specific domain.
The paper tackles the problem of evaluating soccer players' off-ball movements that create scoring opportunities for teammates by comparing actual trajectories with predicted ones using a graph variational recurrent neural network. The results show a significant correlation between the proposed indicator and annual salary, which existing indicators and goals could not explain.
Evaluating the individual movements for teammates in soccer players is crucial for assessing teamwork, scouting, and fan engagement. It has been said that players in a 90-min game do not have the ball for about 87 minutes on average. However, it has remained difficult to evaluate an attacking player without receiving the ball, and to reveal how movement contributes to the creation of scoring opportunities for teammates. In this paper, we evaluate players who create off-ball scoring opportunities by comparing actual movements with the reference movements generated via trajectory prediction. First, we predict the trajectories of players using a graph variational recurrent neural network that can accurately model the relationship between players and predict the long-term trajectory. Next, based on the difference in the modified off-ball evaluation index between the actual and the predicted trajectory as a reference, we evaluate how the actual movement contributes to scoring opportunity compared to the predicted movement. For verification, we examined the relationship with the annual salary, the goals, and the rating in the game by experts for all games of a team in a professional soccer league in a year. The results show that the annual salary and the proposed indicator correlated significantly, which could not be explained by the existing indicators and goals. Our results suggest the effectiveness of the proposed method as an indicator for a player without the ball to create a scoring chance for teammates.