According to Gordon Wittenmeyer of the Sun Times,
Multiple sources told the Sun-Times that the Cubs and Red Sox have requested that their nearly three-month stalemate be resolved by the commissioner, a move apparently initiated by Red Sox president and CEO Larry Lucchino late last month.
The two teams have been at odds at what is fair compensation for a GM, with Lucchino apparently stuck on the word "significant" and believes it means it entitles him to compensation to one of the Cubs top players or prospects.
Wittenmeyer states there's no precedent, but does say "until now the benchmark" has been the Andy McPhail compensation, which consisted of Hector Trinidad, a Class A pitcher and the 10th best prospect in a poor farm system. McPhail, like Epstein, came to the Cubs to take over in what amounts to a non-lateral upward move after winning 2 World Series in the AL. It's difficult to imagine two more similar situations. While we remember a different Andy McPhail now, the truth is he was a rock star too and considered one of the best, if not the best, baseball mind in the game at that time.
Wittenmeyer also states the recent compensation given over to the White Sox for letting Ozzie Guillen was two top 5 prospects from the Marlins system. This is misleading, however, as those rankings were following the 2010 season and both are not considered top prospects now. The two players, relief pitcher Jhan Martinez and infielder Osvaldo Marinez, currently rank 7th and 10th, respectively, in what is frequently regarded as the worst farm system in baseball. Marinez is considered a non-closing reliever and Martinez is projected to be a utility infielder.
The Red Sox want to make a special case for Theo Epstein and receive far more compensation than any team has up until now. That is not likely to sit well with Bud Selig, who is loathe to create new markets and certainly is reluctant to do so for front office personnel.
Most baseball analysts, including Jim Callis, Kevin Goldstein, and Keith Law, seem to think that the player the Red Sox receive isn't likely someone that's going to be particularly valuable.
There is this article by Dave Cameron of Fangraphs that argues that Theo Epstein isn't worth a whole lot more than many of the GM candidates of the past (i.e. Rick Hahn) because smart, analytical GMs have become commoditized.
TangoTiger, meanwhile, argues that from a value standpoint, Epstein is worth a mop-up relief pitcher.
So really, it's the Red Sox Nation against the world on this one.