Note: A B+ rating for your reliever may not appear the first time you do this; cycle through the CPU-generated stats and look for the following:
Games: At least 50
Wins, loses: Any
Saves: If your creating a closer, he should have at least 50 saves or better
Innings pitched: 50+ innings
ERA: Below 3.00
Strikeouts: Any
Hits: Any
BB (walks issued): Any, because you gave the reliever A+ control
You will have some creation points leftover. You could add points to either Pickoff, Batting, or Defense. Add some points to his stamina if you want him to be a long relief pitcher. Do not give him any higher than a B on his stamina, as he will take longer to warm up in the bullpen.