Obstructing the field

Obstructing the field is one of the ten methods of dismissing a batsman in the sport of cricket. It dictates that either batsman can be given out if he wilfully attempts to obstruct or distract the fielding side by word or action. It is governed by Law 37 of the laws of cricket, and is a rare way for a batsman to be dismissed: in the history of cricket, there have been only one instance in Test matches and six occasions in One Day International (ODI) games. In most cases this occurs when a batsman thinks that he is going to be run out and he blocks the ball with his bat or changes his line when running between wickets to block the ball. It is legal to block the ball if, when a batsman is running between wickets, he does not deviate from his course and the ball hits him without the batsman blocking the ball on purpose. It is the sole responsibility of the batsman to not even touch the fielder while catching the ball.

The only time a batsman has been dismissed obstructing the ball in a Test match was in the South African cricket team's tour of England in 1951 when, in the fifth Test, Leonard Hutton top edged the ball and, thinking the ball would hit the stumps, attempted to hit the ball away, thereby preventing the wicket-keeper from catching the ball.

Obstructing the field is Law 37 in the laws of cricket established by the Marylebone Cricket Club (MCC). A batsman can be given out for obstructing the field if he wilfully attempts to obstruct or distract the fielding side by word or action. Law 37 describes the following three circumstances where this applies, but the law is not limited to these circumstances. If, after completing the act of playing the ball, the batsmen wilfully strikes the ball with a hand not holding the bat, unless this is to avoid injury, or any other part of his person or with his bat. The second circumstance is if either batsman should wilfully obstruct or distract a fielder preventing a catch being made. A batsman can also be out if, at any time while the ball is in play and without the consent of a fielder, he uses his bat or any part of his person, including a hand not holding the bat, to return the ball to any fielder. The latter situation is rarely applied, as the fielding side generally accept that the batsman is being helpful in returning the ball. A bowler does not receive credit for the wicket when a batsman is dismissed in this fashion, and any runs that have been completed before the offence is committed are scored (unless the obstruction prevents a catch being made).

...
Wikipedia