Blown Saves occur when a relief pitcher enters a game during a save opportunity situation but allows a tying run to score.
More about Blown Saves Leaders
A blown save is credited to a pitcher when he enters the game with the opportunity to record a save, but allows the tying run to score when he is still pitching. While no reliever wants to be credited with a blown save, to be among the league leaders in blown saves one must be a decent pitcher to consistently be given save opportunities (much in the same way that a player leading the league in losses can’t be awful – otherwise he wouldn’t have so many opportunities to earn a loss). Blown saves are particularly frustrating however, as most take place when a team is three or fewer outs away from earning a win.