It may seem like splitting hairs but in this line of work, small details are what separate Average Joes from superstars.
The art of pitching can be a fickle one. Players can be Cy Young contenders one year and optioned the next. Relievers have it the worst, dealing with small sample sizes and for some, the highest-leverage game situations on a regular basis. It's why closers often have short lifespans these days and few ever manage to maintain elite numbers over an extended stretch.