In the present article, we use simulation and theory to understand the case of flexible and semiflexible tethered polymers in the limit of high shear flows and consequently near-full extension of the chains. We adopt a random-walk picture along the axis of the polymer, which in combination with a statistical mechanical description of perturbations along the chain contour allows us to fully characterize the geometry of the polymer chain without any fit parameters. Incorporation of hydrodynamic interactions is also investigated, with the hydrodynamic lift force inducing changes in the chain equilibrium structure near the tether point that could have implications for adsorption and desorption kinetics.