Did they completely remove all the wood chips down at least 6 inches below the surface? If not then you likely have a nitrogen starvation going on. Decomposing wood buried in the soil will deplete all the nitrogen from the soil for 10 to 20 years.

Solution is to dig up the grass (carefully remove it and keep it moist), remove all the wood as deep as you can go, and replace that empty spot with sand or topsoil. Then put the grass back down.

Hi dchall: I'm not sure what all they did - I was at work while they were working on my yard. I'm a complete novice at lawncare....can you detail how I would go about removing the grass such that I can then replace it after putting down the sand/topsoil? Thanks so much for your response.