The Miami Marlins made the decision before they even went to spring training: They were going to carry eight relievers to go along with five starting pitchers come Opening Day, which means that 13 players on their 25-man roster will be pitchers. No ifs, ands or buts.
In my 15 years as a major league GM, most of the time I had my teams carry 11 pitchers, but we would go to 12 when needed or down to 10 if we had several days off ahead of us on the schedule. However, when I went to 12 pitchers it almost always caused huge problems for my managers, who never felt that they had enough position players to manage the offensive side of the game properly. Teams have sporadically gone to 13 pitchers in the past during the season. As Texas Rangers general manager Jon Daniels put it, "Sometimes we prefer to protect the pitching staff and can go short on the bench for a week or two at a time."
It just isn't something teams do over a full season.
So the Marlins doing so from the get-go as a matter of design represents something new in roster design, especially in the National League. Imagine the impact of a 13-man pitching staff for a field manager like Don Mattingly. Their decision has already had huge ramifications on the way the Marlins do business, both in the front office and with the field staff. And they are not alone, because several other teams are either considering going to 13 more frequently themselves, or evaluating how the Marlins’ plan will work.
"We have carried 13 pitchers as much as anybody the last couple of years," San Francisco Giants general manager Bobby Evans said. "It creates challenges relative to our bench with a backup catcher and then only three guys remaining on the bench."