Distance (Front/Back) can usually be achieved by a high pass/high shelf filter (to simulate the loss of highs as a sound source moves further away in reality), low frequency diffusion, change in volume, increase/decrease in early reflections, increase/decrease in level of the reverb tail.
The early reflections and reverb tail are obviously dependent on the space. Outdoor spaces could do with a few short delays to simulate reflections off nearby obstacles (depends on what't in the video).
Panning (again depending on the movement on the screen) and a touch of a doppler effect (change in pitch) can help make it 'real' as Dave suggested.
Most reverb plugins will give you control over early reflections and the reverb tail. If you are unsure of how to begin, recall a preset that seems like it would match the space visually and tweak from there.
The low shelf filter can be set at about 900Hz and dropped a couple of dB (again depending on the distance that needs to be simulated). Play around with all these controls till it feels and sounds right.
Additionally, in the world of Foley a lot more can be done to simulate distance. As the person gets closer to the camera you could add in a little more of the cloth track, hear more detail in the footsteps (crunch of gravel for example) and also highlight any props/jewellery/sound-making-costume-elements.