We study numerically surfactant effects on the evolution of an injected buoyant drop. In the absence of surfactants, drops start with an initially planar interface, form a pendant shape, and then rapidly form a neck for the case of a viscous drop in a viscous fluid. In prior work, we have shown that the presence of surfactants can significantly alter drop evolution for adsorption-desorption controlled surfactants, with the effects depending strongly on the surface coverage and the Biot number, (the ratio of desorption rates to convection rates), and ranging from perturbed neck shapes to drops which entirely resist necking, and fail to detach. Here, we study surfactants controlled by both adsorption-desorption and bulk diffusion at finite bulk Peclet number. The effect of bulk diffusion gradients on drop shape, neck dynamics and satellite drop formation is probed. One aim of this work is to study the controlling mass transfer process as a function of particle radius. For static systems, we have established that surfactant mass transfer shifts from mixed control at large radii to kinetic control at small radii, with the shift occurring at a length scale determined by surfactant physicochemistry. Here, we seek to extend this work to the injected drop problem.