Ball return is instantaneous

IEnumerator ReturnObject()
    {

        float distanceThreshold = 0.1f;

        // While there is still a small amount of distance between the thrown object and the starting position
        while (Vector3.Distance(throwingObject.transform.localPosition, startingPosition)> distanceThreshold)
        {
            // ... move the ball toward the starting position
            throwingObject.transform.localPosition = Vector3.Lerp(throwingObject.transform.localPosition, 
                                                    startingPosition, 
                                                    Time.deltaTime * objectReturnSpeed);
            // ...if the thrown object is now close to the start position...

            if(Vector3.Distance(throwingObject.transform.localPosition, startingPosition) < distanceThreshold)
            {

                // ...then resent the position directly
                throwingObject.transform.localPosition = startingPosition;
            }
        }
        //... Yield back control to the main script
        yield return null;

    }