(a) The Official Scorer shall charge an error against any fielder:

(1) whose misplay (fumble, muff or wild throw) prolongs the time at bat of a batter, prolongs the presence on the bases of a runner or permits a runner to advance one or more bases, unless, in the judgment of the Official Scorer, such fielder deliberately permits a foul fly to fall safe with a runner on third base before two are out in order that the runner on third shall not score after the catch;

Rule 9.12(a)(1) Comment:

Slow handling of the ball that does not involve mechanical misplay shall not be construed as an error. For example, the Official Scorer shall not charge a fielder with an error if such fielder fields a ground ball cleanly but does not throw to first base in time to retire the batter. It is not necessary that the fielder touch the ball to be charged with an error. If a ground ball goes through a fielder’s legs or a fly ball falls untouched and, in the scorer’s judgment, the fielder could have handled the ball with ordinary effort, the Official Scorer shall charge such fielder with an error. For example, the Official Scorer shall charge an infielder with an error when a ground ball passes to either side of such infielder if, in the Official Scorer’s judgment, a fielder at that position making ordinary effort would have fielded such ground ball and retired a runner. The Official Scorer shall charge an outfielder with an error if such outfielder allows a fly ball to drop to the ground if, in the Official Scorer’s judgment, an outfielder at that position making ordinary effort would have caught such fly ball. If a throw is low, wide or high, or strikes the ground, and a runner reaches base who otherwise would have been put out by such throw, the Official Scorer shall charge the player making the throw with an error.

The Official Scorer shall not score mental mistakes or misjudgments as errors unless a specific rule prescribes otherwise. A fielder’s mental mistake that leads to a physical misplay— such as throwing the ball into the stands or rolling the ball to the pitcher’s mound, mistakenly believing there to be three outs, and thereby allowing a runner or runners to advance— shall not be considered a mental mistake for purposes of this rule and the Official Scorer shall charge a fielder committing such a mistake with an error. The Official Scorer shall not charge an error if the pitcher fails to cover first base on a play, thereby allowing a batter-runner to reach first base safely. The Official Scorer shall not charge an error to a fielder who incorrectly throws to the wrong base on a play.

The Official Scorer shall charge an error to a fielder who causes another fielder to misplay a ball—for example, by knocking the ball out of the other fielder’s glove. On such a play, when the Official Scorer charges an error to the interfering fielder, the Official Scorer shall not charge an error to the fielder with whom the other fielder interfered.

(2) when such fielder muffs a foul fly to prolong the time at bat of a batter, whether the batter subsequently reaches first base or is put out;

(3) when such fielder catches a thrown ball or a ground ball in time to put out the batter-runner and fails to tag first base or the batter-runner;

(4) when such fielder catches a thrown ball or a ground ball in time to put out any runner on a force play and fails to tag the base or the runner;

(5) whose wild throw permits a runner to reach a base safely, when in the scorer’s judgment a good throw would have put out the runner, unless such wild throw is made attempting to prevent a stolen base;

(6) whose wild throw in attempting to prevent a runner’s advance permits that runner or any other runner to advance one or more bases beyond the base such runner would have reached had the throw not been wild;

(7) whose throw takes an unnatural bounce, touches a base or the pitcher’s plate, or touches a runner, a fielder or an umpire, thereby permitting any runner to advance; or

Rule 9.12(a)(7) Comment:

The Official Scorer shall apply this rule even when it appears to be an injustice to a fielder whose throw was accurate. For example, the Official Scorer shall charge an error to an outfielder whose accurate throw to second base hits the base and caroms back into the outfield, thereby permitting a runner or runners to advance, because every base advanced by a runner must be accounted for.

(8) whose failure to stop, or try to stop, an accurately thrown ball permits a runner to advance, so long as there was occasion for the throw. If such throw was made to second base, the Official Scorer shall determine whether it was the duty of the second baseman or the shortstop to stop the ball and shall charge an error to the negligent fielder.

Rule 9.12(a)(8) Comment:

If, in the Official Scorer’s judgment, there was no occasion for the throw, the Official Scorer shall charge an error to the fielder who threw the ball.

(b) The Official Scorer shall charge only one error on any wild throw, regardless of the number of bases advanced by one or more runners.

(c) When an umpire awards the batter or any runner or runners one or more bases because of interference or obstruction, the Official Scorer shall charge the fielder who committed the interference or obstruction with one error, no matter how many bases the batter, or runner or runners, may advance.

Rule 9.12(c) Comment: 

The Official Scorer shall not charge an error if obstruction does not change the play, in the opinion of the scorer.

(d) The Official Scorer shall not charge an error against:

(1) the catcher when the catcher, after receiving the pitch, makes a wild throw attempting to prevent a stolen base, unless the wild throw permits the stealing runner to advance one or more extra bases or permits any other runner to advance one or more bases;

(2) any fielder who makes a wild throw if in the scorer’s judgment the runner would not have been put out with ordinary effort by a good throw, unless such wild throw permits any runner to advance beyond the base he would have reached had the throw not been wild;

(3) any fielder who makes a wild throw in attempting to complete a double play or triple play, unless such wild throw enables any runner to advance beyond the base such runner would have reached had the throw not been wild;

Rule 9.12(d) Comment:

When a fielder muffs a thrown ball that, if held, would have completed a double play or triple play, the Official Scorer shall charge an error to the fielder who drops the ball and credit an assist to the fielder who made the throw.

(4) any fielder when, after a ground ball or dropping a batted ball that is in flight or a thrown ball, the fielder recovers the ball in time to force out a runner at any base; or

(5) any fielder when a wild pitch or passed ball is scored.

(e) The Official Scorer shall not charge an error when the batter is awarded first base on four called balls, when the batter is awarded first base when touched by a pitched ball, or when the batter reaches first base as the result of a wild pitch or passed ball.

Rule 9.12(e) Comment:

See Rule 9.13 for additional scoring rules relating to wild pitches and passed balls.

(f ) The Official Scorer shall not charge an error when a runner or runners advance as the result of a passed ball, a wild pitch or a balk.

(1) When the fourth called ball is a wild pitch or a passed ball and as a result

(A) the batter-runner advances to a base beyond first base;

(B) any runner forced to advance by the base on balls advances more than one base; or

(C) any runner, not forced to advance, advances one or more bases, the Official Scorer shall score the base on balls and also the wild pitch or passed ball, as the case may be.

(2) When the catcher recovers the ball after a wild pitch or passed ball on the third strike, and throws out the batter-runner at first base, or tags out the batter-runner, but another runner or runners advance, the Official Scorer shall score the strikeout, the putout and assists, if any, and credit the advance of the other runner or runners on the play as a fielder’s choice.

Rule 9.12(f) Comment:

See Rule 9.13 for additional scoring rules relating to wild pitches and passed balls.