MLB All-Star Classifier

A machine learning classification task that predicts the players of MLB's annual All-Star Game (position players only). The project implements a random forest model.

The project is written in Python, using the pandas and numpy packages for data analysis, the matplotlib package for data visualization, the pickle library for serialization, and the sklearn library for the machine learning models.

To try the model out for yourself, follow:
data_preprocessing.py → cross_validation.py → generate_team_sizes.py → hyperparam_tuning.py → model_training.py

To collect a season's worth of data, such as for 2018, follow:
bbref/bbref_scraper.py (for each table) → bbref/bbref_parser.py (for each table) → bbref/bbref_normalizer.py

2018 All-Star Team

League	Position	random_forest Prediction	MLB Actual
AL	C	Wilson Ramos, Rays	Wilson Ramos, Rays
AL	1B	Yuli Gurriel, Astros	Jose Abreu, White Sox
AL	2B	Jose Altuve, Astros	Jose Altuve, Astros
AL	3B	Jose Ramirez, Indians	Jose Ramirez, Indians
AL	SS	Manny Machado, Orioles	Manny Machado, Orioles
AL	OF	Mookie Betts, Red Sox	Mookie Betts, Red Sox
AL	OF	Mike Trout, Angels	Mike Trout, Angels
AL	OF	Aaron Judge, Yankees	Aaron Judge, Yankees
AL	Reserve	J.D. Martinez, Red Sox	J.D. Martinez, Red Sox
AL	Reserve	Eddie Rosario, Twins	Salvador Perez, Royals
AL	Reserve	Andrew Benintendi, Red Sox	Mitch Moreland, Red Sox
AL	Reserve	Nicholas Castellanos, Tigers	Gleyber Torres, Yankees
AL	Reserve	Andrelton Simmons, Angels	Jed Lowrie, Athletics
AL	Reserve	Alex Bregman, Astros	Alex Bregman, Astros
AL	Reserve	Francisco Lindor, Indians	Francisco Lindor, Indians
AL	Reserve	Michael Brantley, Indians	Michael Brantley, Indians
AL	Reserve	Whit Merrifield, Royals	Shin-Soo Choo, Rangers
AL	Reserve	Xander Bogaerts, Red Sox	Mitch Haniger, Mariners
AL	Reserve	Giancarlo Stanton, Yankees	George Springer, Astros
AL	Reserve	Nelson Cruz, Mariners	Nelson Cruz, Mariners
AL	Reserve	Jean Segura, Mariners	Jean Segura, Mariners
NL	C	Willson Contreras, Cubs	Willson Contreras, Cubs
NL	1B	Freddie Freeman, Braves	Freddie Freeman, Braves
NL	2B	Javier Baez, Cubs	Javier Baez, Cubs
NL	3B	Nolan Arenado, Rockies	Nolan Arenado, Rockies
NL	SS	Starlin Castro, Marlins	Brandon Crawford, Giants
NL	OF	Nick Markakis, Braves	Nick Markakis, Braves
NL	OF	Matt Kemp, Dodgers	Matt Kemp, Dodgers
NL	OF	Bryce Harper, Nationals	Bryce Harper, Nationals
NL	Reserve	Matt Carpenter, Cardinals	Yadier Molina, Cardinals
NL	Reserve	Jose Martinez, Cardinals	Buster Posey, Giants
NL	Reserve	J.T. Realmuto, Marlins	J.T. Realmuto, Marlins
NL	Reserve	Paul Goldschmidt, D-backs	Paul Goldschmidt, D-backs
NL	Reserve	Joey Votto, Reds	Joey Votto, Reds
NL	Reserve	Ozzie Albies, Braves	Ozzie Albies, Braves
NL	Reserve	Scooter Gennett, Reds	Scooter Gennett, Reds
NL	Reserve	Eugenio Suarez, Reds	Eugenio Suarez, Reds
NL	Reserve	Trevor Story, Rockies	Trevor Story, Rockies
NL	Reserve	Charlie Blackmon, Rockies	Charlie Blackmon, Rockies
NL	Reserve	Brandon Belt, Giants	Lorenzo Cain, Brewers
NL	Reserve	Brian Anderson, Marlins	Christian Yelich, Brewers
NL	Reserve	Jesus Aguilar, Brewers	Jesus Aguilar, Brewers

(Note that the AL's DH position and each league's Final Votes are considered reserve players for convenience.)

Results

Metric	train (1933-2009 data)	test (2010-2017 data)	eval (2018 data)
F1	0.983563	0.599455	0.690476

Credits

Credits to Sean Lahman's Baseball Database for the raw baseball data excluding 2018 (files in data/raw/).

Credits to Baseball Reference for the raw baseball data of 2018.

Also credits to the MLB for, well, existing, as otherwise this project would not have existed. I guess also for selecting this year's official All-Star Team.