Rear sprocket question

[SeaS2R]

I noticed that the rear sprocket on my 08 S2R1K has a bit of rotational play.  Maybe an 1/8th of an inch or so.  This doesn't seem right to me.  Can anybody confirm?  I've never had the rear wheel or sprocket off, though I did recently replace the front sprocket and adjust ride height.  If anybody has ideas of how I might have screwed this up I'd love to hear what I did!

Thanks!

[Slide Panda]

There is a cush drive - there's a series of rubbery cylinders that fit into the wheel and the sprocket, in turn, fits in those rubbery gizmos.  You may just be noticing some free play in that system.  But I'm just theorizing.

Got a buddy with a single swing arm duc you can compare with?