Assume you’re Brian Cashman for a minute. You’ve filled your 40 man roster by this point with plenty of able candidates to assume various roles. You know that you’ll carry your 5-man starting rotation, starting positional 9, a backup Catcher, backup infielder and a 4th Outfielder. Most of your bullpen is set with Mo, either Joba/Hughes, Marte, D-Rob, Aceves and a long man in Gaudin. On a team like the Yanks, most of the roster spots are set before Spring Training even begins. So now you’re now getting down to those last few spots on the roster. You have a choice between another arm in the bullpen (mop-up man or 2nd Lefty) or a platoon hitter who will be your last man on the bench. Which way do you go?

Dave Cameron from Fangraphs recently took on this age-old debate in his usual thorough, comprehensive way. He writes:

Because of the ever increasing size of bullpens, these types of hitting specialists have fallen out of favor. The meager salaries that these guys have had to accept highlights the lack of value that teams are now placing on platoons. With only 13 of 25 roster spots dedicated to position players on most teams, it is becoming far more difficult for teams to accommodate left-right platoons and still have the necessary reserves for their starters in case of injury.

Is that a wise use of roster allocation? I’m honestly not sure. I know there’s been a backlash against the ever increasing bullpen sizes among the sabermetric community, but I haven’t seen much in the way of evidence that specializing your bench is more efficient than specializing your bullpen.

Yes, the 12th pitcher on any given team is usually not very good, often producing at a near replacement level. Even if they pitch decently, the leverage of the innings they are given is usually so low that their overall value is quite low. So a straight comparison between value of platoon guy versus value of the 12th reliever will naturally lead one to conclude that teams would be better off with a larger bench and smaller bullpen.

First, I doubt there is any one answer that will be a rule of thumb for these situations. My answer has always been “It depends on the two players” being considered and the construction of the rest of the roster. If you have a useful bat (even one with stark platoon splits if it complements an area of need elsewhere) with a serviceable glove, it could very well make sense. However, if you have an injury prone or youthful rotation that you don’t figure to get many innings out of, I’ll take the extra pitcher. Put another way, the 2008 Yankees needed the extra arm. The 2010 Yanks could use the extra bat.

A 2nd lefty in the bullpen sounds enticing in the abstract, but would barely get any work on this team and would most likely be Boone Logan, who doesn’t excite me. Further, Dave Robertson has always had a reverse platoon split throughout his professional career at every level. The Yanks figure to get loads of length out of their top 4 in the rotation. CC, Vasquez and Pettitte have been workhorses throughout their MLB careers and AJ Burnett has been durable of late, pitching 200+ innings each of the past 2 seasons. Even Joba will finally have his rules lifted this season, so if he wins the 5th spot in Spring Training and everyone stays reasonably healthy, you could see an inordinate amount of innings get chewed up by the Yankee starting 5. In this scenario, D-Rob and Aceves could be scrounging for work, much less a Mark Melancon type. Chad Gaudin would have to wait for injury or a blowout to get in a game. An 11th or 12th pitcher figures to get very few opportunities  to get in games and if those last two pitchers get any work at all, it figures to be of the very low-leverage variety as Dave Cameron stated above.

However, that last bat on the bench could be a real specialist. If they have someone coming off the bench who kills Lefties, then he could be brought in for late-inning, game changing situations. A potent bat off the bench can force an opposing manager to dig a bit deeper into his bullpen, and we all know how thin and top-heavy most MLB bullpens are. Unlike the 12th pitcher previously discussed, this would be VERY high-leverage work. The type you’d like to give a veteran slugger who’s no longer and everyday player. The late 90′s championship teams had players like Darryl Strawberry and Chili Davis filling this role, to great success.  I’ve previously advocated for Gary Sheffield to fill this role, and I’d still love to see it happen. He’s still enough of a power threat to make managers go Righty-Righty with him, and the fact of the matter is he’s always handled Righthanders well throughout his career. Even last year at age 40 he didn’t display much of a platoon split. With the Yanks having two players in Gardner and Granderson who figure to have trouble with Lefties, you can see plenty of late opportunities for Gary to come in and hopefully break a game open.

In summary, to me it’s all about filling the high-leverage need vs the low leverage. I don’t care who pitches in blowouts, were almost certain to lose those games anyway. Now that I’ve weighed in on this, it’s your turn. In building this roster, would you rather have an extra arm in the bullpen (as most teams do these days) or a pinch hitter you can use late in games?

SPECIAL NOTE: My buddy JMK from RAB has a new blog he’s doing called Mystique and Arua. If NoMaas and The Onion had a baby, it would look something like this. Check it out.