He's fine until he gives up a walk or hit.
Each reliever is given a second rating next to his Relief Endurance rating which we will refer to as his "Closer Endurance". For example, a pitcher who is rated "relief (2/3) has a Relief Endurance of 2 and a Closer Endurance of 3. The Closer Endurance rating is a measure of how many outs a pitcher can maintain his effectiveness in "Closer situations". The rating ranges between 0 and 6, or "N" which means he is not used as a closer.
Closer Situation
A "closer situation" occurs whenever the defensive team has the lead and the tying run is at-bat or on-base from the 9th inning on. When this situation occurs then observe the following rule changes:
Reliever being brought into the game
When bringing a relief pitcher into the game in a closer situation ignore his Relief Endurance rating. Instead use his Closer Endurance rating to determine the number of outs he can record before he loses his effectiveness.
Once this number of outs have been recorded, the pitcher will lose his effectiveness as soon as he allows a hit or a walk. If a pitcher is rated 0, then he loses his effectiveness as soon as he allows a hit or a walk. When a pitcher loses his effectiveness, he has reached his POW.
If the pitcher being brought into the game in a closer situation has a Closer Endurance rating of "N", then he enters the game with the loss effectiveness penalty already in affect (he has reached his POW). For pitchers rated as a "N", this penalty is always in effect starting with the first batter they face in a closer situation.
There's a bit more to the closer rule, which can be found in the SOM Super-Advanced Rules here:
https://www.baseballthinkfactory.org/bt ... mrules.htm