Yeah match fixing is not looked kindly upon
Rule 21
http://content.mlb.com/documents/8/2/2/296982822/Major_League_Rule_21.pdf
(a) MISCONDUCT IN PLAYING BASEBALL. Any player or person connected with a Club who shall promise or agree to lose, or to attempt to lose, or to fail to give his best efforts towards the winning of any baseball game with which he is or may be in any way concerned, or who shall intentionally lose or attempt to lose, or intentionally fail to give his best efforts towards the winning of any such baseball game, or who shall solicit or attempt to induce any player or person connected with a Club to lose or attempt to lose, or to fail to give his best efforts towards the winning of any baseball game with which such other player or person is or may be in any way concerned, or who, being solicited by any person, shall fail to inform the Commissioner (in the case of a player or person associated with a Major League Club) or the President of the Minor League Association (in the case of a player or person associated with an independent Minor League Club) immediately of such solicitation, and of all facts and circumstances connected therewith, shall be declared permanently ineligible.