Woodward was a Navy Lieutenant before he took a job at the WaPo. He performed some sort of liaison role between the JCS and the White House, as a messenger I suppose. He had regular contact with Haig and this made some people suspect Haig could have been Deep Throat.
I still think Haig or another really high-level staffer was their source. The guy they named wasn’t anywhere near high enough on the totem pole to be Deep Throat.