Least Sandpiper
Tail and wings about the same length, small sandpiper, legs may not be as dark as they appear in the photo (see other photos).
BD: The plumage colors on the back this bird are a good match to Sibley's juvenile Least, i.e. the different courses of rufous or white-edged feathers and the large, black, unpointed central spots. With the other characters you noted, Least is a good call.