Fantasy baseball was the parent of all fantasy games, starting out many years ago as rotisserie baseball. The league from which players are chosen is Major League Baseball. Some leagues draw from an American League only universe, meaning fantasy owners are only permitted to choose players who play on American League teams. Some do the same with the National League. Most leagues, however, draw from an “all baseball” universe, meaning players from either league can be chosen. Baseball involves more time commitment than football, as teams play a 162 games schedule over seven months. Like football, fantasy baseball usually ends the last day of the regular season and leaves out the playoffs.
Like in all sports, all leagues can choose their own positions. The standard offensive positions in baseball are these: catcher, first baseman, second baseman, third baseman, shortstop, three outfielders, and a flex (any offensive player). Some leagues also include the ability to specify the type of outfielder (right fielder, center fielder, left fielder), or to add a middle infielder (shortstop or second baseman) or a corner infielder (first baseman or third baseman). Some leagues also use a designated hitter. Pitching positions are simpler: Fantasy owners choose some combination of starting pitchers and relief pitchers. This generally means two or three starting pitchers, two or three relievers, and two or three flex pitchers, which are either starters or relievers.
Baseball has more potential statistical categories than any other sport. Many leagues use what is called a 5 x 5 statistical model: offensive players are credited for runs, batting average, home runs, runs batted in (RBI) and stolen bases; pitchers are credited for wins, saves, strikeouts, earned run average (ERA) and ratio (walks + hits divided by innings pitched, or WHIP). Other offensive categories include on base percentage (OBP), slugging percentage, on base plus slugging (OPS), hits, singles, doubles, triples, walks, and strikeouts. Other pitching categories include appearances, innings pitched, runs, earned runs, walks, losses, holds, strikeouts per nine innings (K/9) and strikeout to walk ratio (K/BB).
Baseball leagues play with different scoring systems. Head-to-head is available in baseball as it is in football, with teams matching up week to week, being awarded wins and losses, and being seeded for a postseason tournament based on this performance. Other baseball leagues also use two other main types of scoring: rotisserie and points only. In rotisserie scoring, points are awarded based on what place your team is in in each statistical category. In points only leagues, points are awarded for each statistical modifier and tallied as the season goes, with the player with the most points at the end of the season being the winner.