THE PENNSYLVANIA STATE UNIVERSITY SCHREYER HONORS COLLEGE DEPARTMENT OF INDUSTRIAL AND MANUFACTURING ENGINEERING PREDICTIVE MODELING AND ANALYTICS FOR PROFESSIONAL BASEBALL: AN ANALYSIS OF INJURIES, PLAYER PERFORMANCE, AND MEDICAL STAFF OPTIMIZATION PATRICK SCHERI SPRING 2020 A thesis submitted in partial fulfillment of the requirements for a baccalaureate degree in Industrial Engineering with honors in Industrial Engineering Reviewed and approved* by the following: Guodong (Gordon) Pang Associate Professor Harold and Inge Marcus Department of Industrial and Manufacturing Engineering Thesis Supervisor Catherine Harmonosky Associate Professor and Associate Department Head of Harold and Inge Marcus Department of Industrial and Manufacturing Engineering Honors Adviser * Signatures are on file in the Schreyer Honors College. i ABSTRACT The research in this paper aims to help Major League Baseball (MLB) teams find the next big competitive advantages within baseball – injury modeling and medical staff optimization. The objective of this research is to create models to predict future injury, and evaluate medical staffing so that teams and players can increase their future performance. The game of baseball is quickly shifting towards analytics and as teams strive to find every advantage possible, they must consider evaluating their medical departments. The research in this paper utilizes a predictive model to indicate the odds of a pitcher requiring Tommy John surgery (a common baseball injury). The model used a variety of variables ranging from basic statistics, pitch selections and velocities, and pitching mechanics to generate an equation for the likelihood a player will require surgery. The model showed that a pitcher’s pitch selection is one of the largest indicators of surgery. Additionally, the number of appearances that a pitcher has over his career, and the duration of the appearances can be predictors of surgery. Following the creation of the predictive model, the staffing of team medical departments was evaluated. A baseline scenario was created using one teams known combination of physicians, team consultants, athletic trainers, physical therapists, occupational therapists, chiropractors, massage therapists, strength coaches, and nutritionists. Four additional scenarios were then created to demonstrate a low budget team, a team that highly values preventative action, a team looking to maximize player satisfaction, and a team looking to minimize overall injury. The tradeoffs between each model came from changes in budget, injury time, and risk. This research is just the beginning for what can be done in analyzing medicine in professional sports. As analytics continue to become a larger part of sports, teams can save millions of dollars and increase performance by analyzing every aspect of their operation. ii TABLE OF CONTENTS LIST OF FIGURES _______________________________________________________________________________________ iv LIST OF TABLES _________________________________________________________________________________________ v ACKNOWLEDGEMENTS _______________________________________________________________________________ vi CHAPTER 1: INTRODUCTION ________________________________________________________________________ 1 1.1 History and Evolution of Baseball Analytics ___________________________________________________ 1 1.2 Implications of Injuries in Professional Baseball _____________________________________________ 3 1.3 Objectives ____________________________________________________________________________________________ 4 CHAPTER 2: A BASIS FOR INJURY MODELING _____________________________________________________ 6 2.1 Motivation ___________________________________________________________________________________________ 6 2.2 Literature Review __________________________________________________________________________________ 8 2.2.1 Biomechanical Evaluation of Injury _______________________________________________________________________ 8 2.2.2 Statistical Evaluation of Injury ____________________________________________________________________________ 9 2.2.3 Evaluation of Injury Model Types ________________________________________________________________________ 10 2.3 Injury Trends in Recent Years ___________________________________________________________________ 11 2.4 A Basic Analysis of Common Injuries ___________________________________________________________ 14 2.5 The Pitcher _________________________________________________________________________________________ 17 2.5.1 The Injuries of a Pitcher ___________________________________________________________________________________ 17 2.5.2 The Physics of Pitching ____________________________________________________________________________________ 18 2.6 Potential Predictors of the Injury Prediction Model _________________________________________ 20 2.7 The Modeling Approach __________________________________________________________________________ 21 CHAPTER 3: PREDICTING FUTURE INJURY _______________________________________________________ 22 3.1 Variable Selection for the Model ________________________________________________________________ 22 3.1.1 Initial Selection of Variables ______________________________________________________________________________ 22 3.1.2 Variable Types _____________________________________________________________________________________________ 24 3.1.3 Variable Parameters and Elimination ____________________________________________________________________ 30 3.1.4 Backwards Selection of Variables ________________________________________________________________________ 31 3.2 Model Type Selection _____________________________________________________________________________ 34 3.2.1 The Linear Model __________________________________________________________________________________________ 34 3.2.2 The Generalized Linear Model (GLM) ____________________________________________________________________ 36 3.3 Model Analysis _____________________________________________________________________________________ 37 CHAPTER 4: MODELING THE MEDICAL STAFFING OF A TEAM ________________________________ 41 4.1 An Overview of a Major League Baseball Team Medical Staff ______________________________ 41 4.1.1 Team Physicians ___________________________________________________________________________________________ 42 4.1.2 Team Medical Consultants ________________________________________________________________________________ 44 4.1.3 Athletic Trainers ___________________________________________________________________________________________ 46 4.1.4 Strength and Conditioning Coaches ______________________________________________________________________ 47 iii 4.2 Modeling the Medical Staff _______________________________________________________________________ 48 4.3 Evaluating Tradeoffs within a Medical Staff ___________________________________________________ 50 CHAPTER 5: CONCLUSION ___________________________________________________________________________ 56 5.1 Summary of Findings ______________________________________________________________________________ 56 5.2 Future Research ___________________________________________________________________________________ 59 CITATIONS _____________________________________________________________________________________________ 60 ACADEMIC VITA _______________________________________________________________________________________ 62 iv LIST OF FIGURES Figure 1: Total Cost of Player Injuries ..................................................................................... 6 Figure 2: Number of Player Injuries ........................................................................................ 7 Figure 3: Yearly Trends of Injuries.......................................................................................... 13 Figure 4: Monthly Analysis of Injuries .................................................................................... 14 Figure 5: Shoulder Injury Seasonal Trend ............................................................................... 15 Figure 6: Elbow Injury Seasonal Trend ................................................................................... 15 Figure 7: Hamstring Injury Seasonal Trend ............................................................................. 16 Figure 8: Knee Injury Seasonal Trend ..................................................................................... 16 Figure 9: Back Injury Seasonal Trend ..................................................................................... 17 Figure 10: Sequential Mechanics of a Pitch ............................................................................. 19 Figure 11: Comparison of Basic Pitching Statistics ................................................................. 25 Figure 12: Comparison of Pitch Selection ............................................................................... 27 Figure 13: Comparison of Pitch Movement ............................................................................. 28 Figure 14: Pitch Movement (X) ............................................................................................... 29 Figure 15: Pitch Movement (Z) ............................................................................................... 29 Figure 16: Variable Selection .................................................................................................. 33 Figure 17: Normal Q-Q Plot of Linear Model ........................................................................