An insert device can straddle an existing production string port into the annulus such as through an open sliding sleeve so that annulus access into the production string is available. An injection string is associated with the insert to allow placement of the injection fluid at the desired location even if that location is below an isolation packer. The port can be part of an existing ported sub such as a sliding sleeve. Alternatively, the port can be created at a desired location and the insert supported with an anchor so that spaced seals straddle the port that is created to allow injection access from the annulus into the production tubing. The produced fluids pass around the injection tubing and through the insert body to get to the surface. The insert can be removed if needed.