The first baseman must also field bunts and pick-off throws from the pitcher. Left-handed throwers actually have an advantage at first base since the first baseman's only challenging throws are to third or second base in an attempt to force out a baserunner. Right-handed throwers often use the same technique of throwing to the opposite side of the field to beat their opponent out.
The left-hander has a clear advantage because all of the first baseman's throws go into right field, allowing him to watch more balls get hit toward middle-and-short fields. The first baseman's job is also easier with a left-handed batter because he doesn't have to worry about getting pitched around if the ball is put in play up the middle or towards the power alley in right field. A right-handed batter who does well against lefties will often take some pitches before hitting into a double play but fail to drive anything else. A left-handed batter who does well against right-handers will usually walk some people but still manage to score plenty of runs.
In conclusion, first basemen are left-handed because they can watch more balls get hit toward middle-and-short fields and it makes their jobs easier when there's a left-handed batter on deck.
The first baseman also fields ground balls hit to his position. Right-handed throwers must field their own balls and those of right-handed hitters.
Left-handed swingers tend to play first base because they're less likely to see any action if they're also pitching. Most major league teams have one starter for each game who is required by rule to be listed as a pitcher on the roster. This person is usually named after the team's best left-handed hitter (i.e., Lee Smith or Randy Jones). If this player were a right-hander, he could not be listed as a pitcher since there is no such thing as a left-handed pitcher.
Generally speaking, left-handers are better than right-handers when it comes to batting back-to-back. This is why most teams have one guy start on both sides of the ball; they can't afford to miss any time off the bench. However, since there's no real difference between left-handed and right-handed pitchers except that you'll see more lefties at the plate, most players will just focus on one side of the ball and be fine.
To stop a ball hit down the line by a known left-handed pull hitter, the first baseman will position himself closer to the foul line. To prevent a bunt on the first base side of the infield, the first baseman will position himself in front of the base and advance towards the batter as the ball is thrown.
According to baseball writer and historian Bill James, good defensive first basemen may play off first base and field ground balls hit to the fair side of first base. The first baseman must then rely on the pitcher to cover first base in order to complete the out.
Throwing right-handed will always give you a little edge. Right-handed throwers, for example, are virtually usually used as catcher, middle infielder, and third baseman, according to Pomrenke. Right-handers are just as good as left-handers at first base and in the outfield corners. However, they have an advantage at the plate because there are more pitches to hit out of the hand throwing right-handed. Overall, right-handedness is advantageous but not decisive.
In addition to this, right-handed hitters have an advantage over left-handed hitters because there are more pitches to hit out of the hand throwing right-handed. This means that right-handed hitters have an opportunity to get hits with pitches thrown by left-handers more often than left-handed hitters can get hits with pitches thrown by right-handers.
Right-handed pitchers have an advantage over left-handed pitchers because there are more pitches to strike out against throwing right-handed. This means that right-handed pitchers can rack up strikeouts against left-handers more often than left-handed pitchers can do the same against right-handers.
Here are the numbers: right-handed players are likely to be pitchers or batting right-handed, while left-handed players are likely to be pitchers or batting left-handed.