A study of the possibility of using an absorption model to obtain a unique s-wave I=0 ππ phase shift from the reaction π-p-->π-π+n was made. Applying the model to combined data from several latoratories, we obtained a set of reasonable (but twofold ambiguous) values for the isospin-zero s-wave phase shift δ00, using the isotropic moment of the dipion decay distribution. Values for δ00 deduced by using the s-p wave interference term in the dipion decay cross section agreed well with previous (twofold ambiguous) results obtained by extrapolation procedures. Comparing the two sets of twofold ambiguous solutions for δ00, the lower or "down" branch was preferred marginally in the dipion mass region below the ρ meson. No unique conclusion could be drawn in the higher-mass region. We emphasize the model dependence of these results, but we believe that similar studies with improved statistics for -t>μ2 would yield similar results. Good data for -t<μ2 are required to do definitive model-independent analyses.