Backup catchers tend to be very poor fantasy players, and will actually drag your team down in categories like batting average more than they would help you in any other category. Therefore, just carry the minimum number of catchers and stream players in at other positions. Also, keep in mind that many Yahoo leagues have a maximum number of games played at each position.
Author of: http://MLBMockDraftSoftware.blogspot.com/
Author of: http://dodgerSims.blogspot.com/
Author of: http://TheSoberAngels.blogspot.com/
Author of: http://XeiOnSports.blogspot.com/