most "promotions" and position changes are a nice way of them trying to move you somewhere useful rather than just getting rid of you entirely.
I've seen this happen a "lot" in my industry..
Here's a couple of questions to figure out..
Are they doing this as part of a larger plan, or to keep you happy and give you more money?
If the the former, then you need to figure out what they plan to do with your current position. Hire an outsider? Promote someone from the team? Shrink the team?
If they plan to promote someone from the team, and you refuse your promotion, It could trickle down and you could end up reporting to someone currently in the team..
Variables don't; constants aren't.