Obstruction?

[Andy]

Two things have to happen in order to call obstruction:

The fielder does not have the ball -and-
The fielder without the ball impedes the runner

Your situation tells us nothing about the runner prior to the fielder having the ball. Where the fielder is standing, in and of itself, is not the basis for an obstruction call.

The question that needs to be answered is - Was the runner impeded (slowed down, changed direction, stutter stepped, etc.) by the fielder before the fielder had the ball? If the answer to that question is YES, then you have obstruction.