MSR Silicon Valley is a satellite office, smaller than Redmond, Cambridge, Beijing, and probably several others. Still, it employs (employed?) some heavy hitters, including Turing Award winner Leslie Lamport. Many of these people will probably receive offers to relocate, per the article, but presumably not everyone wants to move to Redmond, hence the existence of the SV lab in the first place. So some will leave Microsoft and seek jobs elsewhere, as will all the researchers that don't receive relocation offers.

As some of my grad student friends have observed, this may be a tough year to be on the academic/research job market...