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MLB Visualizations with baseballr and sdvplotR

Source: vignettes/mlb-viz.Rmd
mlb-viz.Rmd

Introduction

This vignette demonstrates how to create rich MLB visualizations by combining baseballr for player and team data with sdvplotR for team logos, headshots, colors, and gt tables.

Setup 

library(sdvplotR)
library(ggplot2)
library(baseballr)
library(dplyr)
library(gt)

# Get valid MLB team abbreviations
mlb_teams <- valid_team_names("mlb")
head(mlb_teams)

Loading MLB Data

Use baseballr to load team and player statistics from the MLB Stats API:

# The last completed regular season (it ends around October 1)
season <- as.integer(format(Sys.Date(), "%Y")) -
  (format(Sys.Date(), "%m-%d") < "10-05")

# One row per team: abbreviation, name and division
teams <- baseballr::mlb_teams(season = season, sport_ids = 1) |>
  select(team_id, team_abbreviation, team_name = team_full_name, division_name)

# Standings for both leagues (one string: mlb_standings() rejects a vector)
team_stats <- baseballr::mlb_standings(season = season, league_id = "103,104") |>
  transmute(
    team_id = team_records_team_id,
    wins = team_records_wins,
    losses = team_records_losses,
    win_pct = as.numeric(team_records_winning_percentage),
    runs_scored = team_records_runs_scored,
    runs_allowed = team_records_runs_allowed
  ) |>
  inner_join(teams, by = "team_id")

# Season hitting stats for every player, keyed by MLBAM ID
player_stats <- baseballr::mlb_stats(
  stat_type = "season",
  stat_group = "hitting",
  season = season,
  player_pool = "All"
)

The MLB Stats API writes some team abbreviations differently from ESPN (AZ, CWS); sdvplotR accepts either.

MLB Team Performance

Plot every team’s runs scored against runs allowed, with team logos:

ggplot(team_stats, aes(x = runs_scored, y = runs_allowed)) +
  geom_sdv_logos(
    aes(team = team_abbreviation),
    sport = "mlb",
    width = 0.06
  ) +
  scale_y_reverse() +
  labs(
    title = "MLB Runs Scored and Allowed",
    subtitle = paste("Season", season),
    x = "Runs Scored",
    y = "Runs Allowed (fewer is better)",
    caption = "Data: baseballr | Viz: sdvplotR"
  ) +
  theme_minimal()

MLB Team Colors

Use team colors to show winning percentage:

team_wins <- team_stats |>
  arrange(desc(win_pct)) |>
  head(20)

ggplot(team_wins, aes(x = reorder(team_abbreviation, win_pct), y = win_pct)) +
  geom_col(aes(fill = team_abbreviation), width = 0.7) +
  scale_fill_sdv(sport = "mlb", alpha = 0.8) +
  scale_y_continuous(labels = scales::percent) +
  labs(
    title = "Top 20 MLB Teams by Winning Percentage",
    x = NULL,
    y = "Winning Percentage"
  ) +
  theme_minimal() +
  theme(
    axis.text.x = element_text(angle = 45, hjust = 1),
    legend.position = "none"
  )

Player Headshots

Plot the home run leaders with their headshots:

top_hr <- player_stats |>
  slice_max(home_runs, n = 8, with_ties = FALSE)

ggplot(top_hr, aes(x = games_played, y = home_runs)) +
  geom_sdv_headshots(
    aes(player_id = player_id),
    sport = "mlb",
    id_type = "league",
    height = 0.15
  ) +
  geom_label(
    aes(label = player_full_name),
    nudge_y = -3,
    size = 3,
    alpha = 0.7
  ) +
  labs(
    title = "MLB Home Run Leaders",
    subtitle = paste("Season", season),
    x = "Games Played",
    y = "Home Runs"
  ) +
  theme_minimal()

MLBAM player IDs

The MLB Stats API and Baseball Savant identify players by their MLBAM ID, not their ESPN athlete ID, which is why these headshots pass id_type = "league": it draws MLBAM IDs from MLB’s own image CDN. Leave id_type unset for ESPN athlete IDs, such as those in baseballr’s espn_mlb_*() data. Both are plain numbers, so the wrong setting draws someone else or nothing.

MLB Team Tiers

Create a tier plot ranking MLB teams:

# Sample tier assignments
tier_data <- data.frame(
  tier_no = c(1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5),
  team = c("LAD", "ATL", "HOU", "BAL", "TB", "NYY",
           "PHI", "TEX", "TOR",
           "SEA", "SF", "CHC",
           "BOS", "STL", "CIN")
)

sdv_team_tiers(
  tier_data,
  sport = "mlb",
  title = "MLB Power Rankings",
  subtitle = paste("As of", Sys.Date()),
  tier_desc = c(
    "1" = "World Series Favorites",
    "2" = "Contenders",
    "3" = "Playoff Teams",
    "4" = "Bubble Teams",
    "5" = "Rebuilding"
  )
)

MLB Division Map

Show each division’s teams in a column:

division_map <- teams |>
  mutate(division_num = as.numeric(factor(division_name))) |>
  arrange(division_num, team_name) |>
  group_by(division_num) |>
  mutate(team_rank = row_number()) |>
  ungroup()

ggplot(division_map, aes(x = division_num, y = team_rank)) +
  geom_sdv_logos(
    aes(team = team_abbreviation),
    sport = "mlb",
    width = 0.075
  ) +
  scale_x_continuous(
    breaks = seq_along(levels(factor(division_map$division_name))),
    labels = levels(factor(division_map$division_name))
  ) +
  scale_y_reverse() +
  labs(
    title = "MLB Teams by Division",
    x = NULL,
    y = NULL
  ) +
  theme_minimal() +
  theme(
    axis.text.x = element_text(angle = 45, hjust = 1),
    axis.text.y = element_blank(),
    panel.grid = element_blank()
  )

MLB Standings Table with Logos

Create a gt table with team logos:

team_wins |>
  head(15) |>
  mutate(rank = row_number(), logo = team_abbreviation) |>
  select(rank, logo, team_name, wins, losses, win_pct) |>
  gt() |>
  gt_sdv_logos(columns = "logo", sport = "mlb", height = 35) |>
  fmt_number(columns = "win_pct", decimals = 3) |>
  cols_label(
    rank = "#",
    logo = "",
    team_name = "Team",
    wins = "W",
    losses = "L",
    win_pct = "Pct"
  ) |>
  tab_header(
    title = "MLB Top 15",
    subtitle = paste("Season", season)
  )

Player Performance Comparison

Compare the home run leaders with the batting average leaders among qualified hitters:

qualified <- baseballr::mlb_stats(
  stat_type = "season",
  stat_group = "hitting",
  season = season,
  player_pool = "Qualified"
)

comparison <- bind_rows(
  player_stats |>
    slice_max(home_runs, n = 5, with_ties = FALSE) |>
    transmute(player_id, category = "Home Runs", value = home_runs),
  qualified |>
    mutate(value = as.numeric(avg)) |>
    slice_max(value, n = 5, with_ties = FALSE) |>
    transmute(player_id, category = "Batting Average", value)
) |>
  group_by(category) |>
  mutate(rank = row_number()) |>
  ungroup()

ggplot(comparison, aes(x = rank, y = value)) +
  geom_sdv_headshots(
    aes(player_id = player_id),
    sport = "mlb",
    id_type = "league",
    height = 0.2
  ) +
  facet_wrap(~category, scales = "free_y") +
  scale_x_continuous(breaks = 1:5) +
  labs(
    title = "MLB Top Performers",
    subtitle = paste("Season", season),
    x = "Rank",
    y = NULL
  ) +
  theme_minimal()

Axis Labels with Logos

Replace axis labels with team logos (theme_x_sdv() needs the ggtext package, and goes after any complete theme such as theme_minimal()):

top_8 <- team_wins |>
  head(8) |>
  mutate(team_abbreviation = factor(team_abbreviation, levels = team_abbreviation))

ggplot(top_8, aes(x = team_abbreviation, y = win_pct)) +
  geom_col(aes(fill = team_abbreviation), width = 0.6) +
  scale_fill_sdv(sport = "mlb", alpha = 0.7) +
  scale_x_sdv(sport = "mlb") +
  theme_minimal() +
  theme_x_sdv() +
  labs(
    title = "Top 8 MLB Teams by Winning Percentage",
    x = NULL,
    y = "Winning Percentage"
  ) +
  theme(legend.position = "none")

Next Steps