  Motivated by compelling advances in manipulating cold Rydberg (Ry) atoms in
optical traps, we consider the effect of large extent of Ry electron wave
function on trapping potentials. We find that when the Ry orbit lies outside
inflection points in laser intensity landscape, the atom can stably reside in
laser intensity maxima. Effectively, the free-electron AC polarizability of Ry
electron is modulated by intensity landscape and can accept both positive and
negative values. We apply these insights to determining magic wavelengths for
Ry-ground-state transitions for alkali atoms trapped in infrared optical
lattices. We find magic wavelengths to be around 10 $\mu \mathrm{m}$, with
exact values that depend on Ry state quantum numbers.
