A "floater" is a worker whose regular routine is to move from place to place (within a given company). For example, a library system with many branch libraries might have a few "floaters" who move from branch to branch as needed when regular staff members are sick, on vacation, etc. So, for example, when my favorite librarian disappeared from my local library I asked if he had been transferred to a different branch, and was told that he is now a floater - he goes wherever they need an extra person.