On-shell consistency of the Rarita-Schwinger field formulation

We prove that any bilinear coupling of a massive spin-3/2 field can be brought into a gauge-invariant form suggested by Pascalutsa by means of a nonlinear field redefinition. The corresponding field transformation is given explicitly in a closed form and the implications for chiral effective field theory with explicit {delta}(1232) isobar degrees of freedom are discussed.