3 An error is penalized against any fielder who collects a thrown ball or fields a ground ball in time to put out any runner on a force play but fails to tag the base or the runner, including a batter-runner on a first-base play. 14.21 (a) If an error is made on a foul ball, the umpire should signal the error by waving his/her arm in the air. If no umpire is present, then a member of the National Federation of State High School Associations may signal an error on a foul ball.
There are three ways that an error can be committed: tagging up too soon, failing to tag up properly, or leaving the bag empty. Tagging up too soon means that you have not reached all four bases before returning to the bag. This is an illegal action and results in an automatic throw-out. If you are unsure if you tagged up too early, wait until the ball is back in your team's territory before putting your hands on the bag.
Tagging up improperly means that you failed to touch each base before returning to the bag. Like tagging up too soon, you must wait for the ball to return to your team's territory before putting your hands on the bag. However, instead of getting credit for a base, you will receive a warning from the umpire.
(a) The Official Scorer shall charge an error against any fielder: If a throw is low, wide, or high, or contacts the ground, and a runner who would otherwise have been thrown out reaches base, the Official Scorer shall charge an error against the player making the throw. If a runner is safe at first when the ball is played, the umpire shall call "Safe" and signal for the runners to start running. If however, the ball hits a fan behind the plate or anywhere else in fair territory, the umpire has the discretion to allow either runner to remain at first until he sees how they react to being given a chance to score. This decision must be made before the next pitch is delivered by the pitcher. It is important that fair territory is defined as anything more than 60 feet from home plate. For example, if the ball goes into the stands beyond the reach of someone in the front row of seats, this is not fair territory.
An error can also be charged if a batter fails to touch all parts of the field while he is standing in the batter's box. For example, if he stays too long in one spot, a fielder may steal a base with no fear of being called for interference. Or, if a batter points directly at a defender waiting to catch a pop-up, he has committed an act of intentional baseball. In either case, an error is awarded to the other team.
Fielders who commit obstruction or interference result in runners being awarded bases. When attempting a double play, no errors are assessed as long as one runner is thrown out. A shortstop, for example, takes a ground ball, steps on second to grab the runner coming from first, and throws wildly to first base. The batter-runner is awarded a base on balls because the throw was not made in time. If the shortstop had not stepped up, then both runners would have been safe at first and second with no outs.
If a fielder misses an easy catch he can always try to make another attempt but if it looks like there's no way to get the ball he should just give up and not waste any more energy. You can't be perfect all the time even if you're a professional athlete. Mistakes will be made because human beings are not designed to be able to do this kind of work accurately every time.
In conclusion, fielders can miss easy catches and they can also make difficult ones look easy. It's important for them to know their assignments well and pay attention during games so they don't make any mistakes. Everyone makes mistakes from time to time even professionals so don't be too hard on yourself when this happens.
If a throw is low, wide, or high, or contacts the ground, and a runner who would have been out otherwise reaches base, the official scorer shall charge the player who made the throw with an error. Unless a particular regulation states otherwise, the Official Scorer shall not mark mental blunders or misjudgments as errors.
With that in mind, I quickly scanned the official rule book on MLB.com and produced a list of some of the most unusual laws contained in the rule book.
If a throw is low, wide, or high, or contacts the ground, and a runner who would have been out otherwise reaches base, the official scorer shall charge the player who made the throw with an error. For example, if a pitcher throws at a batter and misses, the batter runs home, and then later scores, it is legal for the batter to go to first base because the pitcher committed an error.
There are three ways that a pitcher can commit an error: by throwing (or hitching) a ball; by ill-handling a ball (e.g., dropping it); and by failing to cover first base (if the batter reaches first base before the pitcher completes his delivery). A catcher also commits an error by not catching a ball thrown by another player.
An error should be charged against a pitcher if one of his attempts at a strike fails to reach the plate and the opponent takes a base on balls, either through contact or via failure to touch all four bases. If there is no appeal, then the batter is awarded a free base. However, if the pitcher was not trying to strike the man out, but rather wanted him to walk so he could take advantage of a double play situation, then no error has been committed and the batter should not be awarded a free base.