In baseball, all positions of play are explained from the perspective of the view of the field from the stands, which is also the perspective of the homeplate umpire.
Each team fields nine players in defensive positions. Those positions are:
Pitcher: positioned on the mound and throws each pitch. Responsible to the 1st baseman and the catcher as backup, or second line of defense, for plays at either of their plates.
Catcher: positioned behind home plate and catches each pitch. Responsible for the defense of home plate.
1st Baseman: positioned at first base and is responsible for the defense of the base and area between homeplate and the base.
2nd Baseman: positioned between 1st and 2nd base and is responsible for the defense of 2nd base and surrounding area to the right of the base.
3rd Baseman: positioned at third base and is responsible for the defense of the base and surrounding area to the right of the base.
Shortstop: positioned between 2nd and 3rd base and is responsible for defense of the space left of 2nd and right of 3rd base.
Left Fielder: Backup to 3rd base and the shortstop, the left fielder defends the left portion of the outfield.
Center Fielder: Backup to the shortstop and the 2nd baseman, the center fielder defends the middle portion of the outfield.
Right Fielder: Backup to the 2nd baseman and the 1st baseman, the right fielder defends the right portion of the outfield.
All of the “fielder” positions make up the outfield of the teams defense. The remaining positions are the infield. Someone who plays these positions is called an outfielder or infielder respectively. The infield consist of the dirt area from surrounding home plate and all 3 bases. The outfield of a baseball diamond is the grass area that lies outside the infield. The grass area inside the base paths (including the pitcher's mound) is part of the infield. Together the pitcher and catcher are referred to as the battery.
Each defensive position has two abbreviations. The first set is used in the standings, the second for scorekeeping.
Standings are records of how a player has performed individually. They include a number of offensive and defensive statistics. Pitchers have more statistics than position players on defense.
P = Pitcher
C = Catcher
1B = 1st Baseman
2B = 2nd Baseman
3B = 3rd Baseman
SS = Shortstop
LF = Left Fielder
CF = Centerfielder
RF = Right Fielder
Standings are also used to show of how a team is performing compared to other teams within their division or league.
In scorekeeping, each position is given a number value. This enables a scorekeeper to record the plays on the field in quicker succession. For example, if the batter hits to the shortstop, who then throws the ball to the 1st baseman for the out, the scorekeeper would simply write 6-3 and record an out in the checkbox for outs on the score sheet. Here are the position values:
P = 1
C = 2
1B = 3
2B = 4
3B = 5
SS = 6
LF = 7
CF = 8
RF = 9
In addition to their duties of defense, many position players have responsibilities on the field to their fellow players.
The two positions that act like back-up coaches, taking a role similar to point guard on a basketball team, are the catcher and the shortstop. The catcher is responsible to assist the infielders while the shortstop acts as a second set of eyes for the outfielders.
In addition to catching each pitch, defending homeplate and backing up the infield plays, a catcher determines which pitch a pitcher will throw to each batter. Catchers also help position infield players when they see certain batting techniques, for example bunting, potentially being used against their team. The catcher coordinates each of the position players in the infield to ensure they are in the best possible position to defend the field in every situation.
Shortstops rely messages from the catcher to help coordinate the players in the outfield. Using the bunting example, players in the outfield, normally positioned further back, would be moved in. In the case of a homerun hitter where the game is on the line, they may be moved back because the batter is more likely to try to swing big in an attempt to hit over the fence.
The shortstop also relays game information to the outfield including number of outs in the inning and plays called from the dugout. This is because the catcher and coach are simply too far away from the outfielders for them to be able to see many of the hand singles, including the pitch count and other information provided to them by the umpire behind home plate. Shortstops also have a unique view. The can see the offensive team’s first-base coach, the person responsible for telling the runners when to go. He can also see his own team’s dugout. This means he can potentially see when a coach is sending a player to 2nd and prepare the infield to attempt to get him out by relying that message back to the catcher who then signals the pitcher. He can also receive and rely calls from his own bench to his teammates.
The pitchers also make up a very unique line of defense, taking on different roles themselves. There are three types of pitchers on staff.
Starting Pitchers: These pitchers start the game and are generally expected to throw between 100-120 pitches in a game. This can, often times, mean they throw an entire game but more often, it means they throw into the 7th inning.
Relief Pitchers: A Relief pitcher is called in on days when the starter is having trouble staying ahead in the count, for example throwing more balls than strikes. This can indicate a pitcher has become too tired to continue throwing their best pitches and so the relief pitcher is brought in to help out.
Closers: A closer is a pitcher that is generally brought in, in the final 1-2 innings of the game to help insure a lead. They are known as strikeout pitchers and generally throw very fast. As players tire their hand-eye coordinate slows down so bringing in a fresh, fast arm can often times help maintain a lead.