Sorry to Quibble, But He's Called a 'Gribble'

We have starters.
We have relievers of all stripes--closers, set-up men, mop-up men.
But what about the guys who both start and relieve?
They are, or at least should be, called "gribbles," posits Russell Carleton of the "Just a Bit Outside" blog on FoxSports.com.
If you're wondering about gribble's etymology, I don't believe it has any. It's just a fun word. It's also "any of about 56 species of marine isopod from the family Limnoriidae. (pictured right) They are mostly pale white and small crustaceans," says Wikipedia. Urban Dictionary, meanwhile, says that "gribble," in Hawaii, means falling, or "eating it." 
So maybe there's a touch of etymology there--the sometimes starter/sometimes reliever simply eats innings.
Carleton, in a detailed essay making the case for six-man rotations, notes that those starters-relievers are at times called a "swingman." That's really a euphemism, he says, for:
...€œthe guy who made the team as a minor-league invite and who we mostly send out there as a sacrificial lamb when we'€™ve run out of other warm bodies and who will probably be sent to AAA at the next convenient opportunity."€
I wonder if teams would do this if they could say to a pitcher, "€œWe want you to be a gribble for us,"€ and everyone knew what that meant.

The gribble could revolutionize baseball, says Carleton:
A team that embraced this six-man rotation model and who could convince three guys to take on this new/old gribble/swingman role could probably find guys whom the league only valued as back-end starters and turn a bit of straw into gold as a result.