I have a whirpool tub that was draining slowly, so I took out the stopper and when I looked down the drain it was off center, by half. Should it be like that due to the type of tub/venting or whatever? Or is it installed wrong? How do I fix this?

This is a typical trap hook up for a whirlpool tub.(see image). If yours is different take a picture and let us see. Regards, Tom