From BR Bullpen

A hold is an unofficial statistic that measures the effectiveness of middle relievers. A hold is granted to a relief pitcher who enters a game with his team in the lead in a save situation, and hands over that lead to another reliever without the score having been tied in the interim. A pitcher cannot get credit for a hold in a game in which he is credited with either a win or a save (although some sources may grant those decisions in the very exceptional situation where a pitcher moves to another position and later resumes pitching); It is possible for a pitcher to receive a hold and a loss in the same game should he exit with the lead, only to see his bequeathed runners score the tying and go-ahead runs.

A pitcher who comes into a game and is eligible for a hold and fails in his mission is charged with a blown save; there is no such thing as a blown hold.

As the hold is not an official statistic, there is no consensus whether a pitcher needs to record an out or pitch effectively to get credit for a hold. Some compilers consider that the mere fact of not surrendering the lead is sufficient, while most observers consider that the other two criteria should also apply. The lack of consensus on this issue means that hold totals vary from source to source.

The hold statistic was designed to be a more effective measure of the role of middle relievers. As it stands, they are charged with a blown save when they fail in their mission, but usually have no chance or registering the save if they are successful, as that is the closer's prerogative. Given this, ignorant commentators will say that a certain middle reliever is not cut out to succeed as a closer as his save percentage (saves divided by save opportunities) is very low, which is ridiculous when one thinks about it. Save percentage for a middle reliever should in fact be calculated by dividing saves + holds by saves + holds + blown saves.

Baseball-reference.com only lists holds among its statistics for pitchers if one moves the cursor above a pitcher's save totals for the year; this will reveal the number of holds and blown saves, as the two numbers do not have dedicated columns. In addition, its Pitching Game Finder does allow "Hold" to be selected.

The single-season record for holds is 41, set by Joel Peralta in 2013 and tied by Tony Watson in 2015. In 2021, Watson became the all-time career leader with 232, moving ahead of Arthur Rhodes. The caveat is that this is counting only from 1999 onwards, when Major League Baseball began to keep track in spite of the statistic's unofficial status; Rhodes had recorded a number of holds before that artificial cut-off date.