I fully expect Betts to have a great year, with a higher WAR than Lux and May combined. That's not much of a prediction, comparing a HOFer to two guys entering what they hope will be their first full years in the majors... but that's the trend here. Even if he gets traded, Mookie will be hounded by reporters all season about extensions he won't sign and where he will sign, so I don't think his production will be affected much by location. Personally, I -- like many Red Sox fans -- prefer it be in Fenway.
However, the distractions of the Betts situation may be most stressful of all for the front office in Boston. Imagine if Bloom can't get what he wants, Mookie stays, and hits the ground running like two years ago. If the Sox get off to a good start, the brass will be under more pressure than ever from fans and especially the fickle, two-faced media to "lock him up, give him the $400 million already!"
Then Mookie will counter with half a billion.