The pitcher who allows the runner who scores the winning run to reach base is the losing pitcher. For example: Abel is the starting pitcher. The game is tied at 1-1. Abel gives up hits to Mike and Ollie, who are now at 1st base and 3rd base. Abel is relieved by Basil. Basil gets the next 2 batters on strikeouts. The next batter, Joel, singles, driving in the runner from 3rd base, so it is now 2-1. Abel will be the losing pitcher if his team scores no more runs, because Abel allowed Mike to be on 3rd base to begin with. To continue this scenario, let's say Abel and Basil's team scores 3 runs in the next half inning, making the score 4-3 in favor of Abel's team. Abel can no longer be the losing pitcher. Basil however, is relieved by Carl, who gives up a home run, tying the score at 4. He is relieved by Doug, who comes in with 1 out and no runners on base. Doug gives up a homer, putting Mike's team ahead by a run, and alas, we are out of innings. Doug allowed the runner to reach base who scored the winning run, and he therefore is the losing pitcher. The winning pitcher in this scenario is whichever lucky guy was the last to pitch for Mike's team, because he was the current opposing pitcher when the winning run scored. I sure hope this made sense!

(e) Regardless of how many innings the first pitcher has pitched, he shall be charged with the loss of the game if he is replaced when his team is behind in the score, or falls behind because of runs charged to him after he is replaced, and his team thereafter fails either to tie the score or gain the lead. This also goes for relievers as well, if he is replaced after giving up the go ahead run(s) or his team falls behind because of runs charged to him after he is replaced, and his team thereafter fails either to tie the score or gain the lead, he will be charged with the loss. http://www.mlb.com/NASApp/mlb/mlb/official_info/official_rules/official_scorer_10.jsp 10:19