  We put forth a program for perturbatively quantizing the bosonic sector of
the IIB superstring on AdS_5xS^5 in the large radius of curvature R (i.e.
flat-space) limit, and in light-cone gauge. Using the quantization of the
massive particle on AdS_5xS^5 as a guiding exercise, we read off the correct
scaling of the particle coordinates in the large radius limit. In the
corresponding large \sqrt{\lambda}=R^2/\alpha' limit of the string the
oscillator modes must be scaled differently from the zero modes. We compute the
bosonic string Hamiltonian in this limit which gives the flat-space
mass-squared operator at leading order, followed by a harmonic oscillator
potential in the zero modes at subleading order. Using these ingredients we
calculate the leading and sub-leading terms in the conformal dimension of the
length-four Konishi state in the large-\lambda limit. Furthermore we work out
the relevant terms of the energy expansion to next-to-next-to leading order,
which are plagued by severe ordering ambiguities. This prevents us from
determining the corrections to the spectrum at order {\lambda}^{-1/4}.
