In Rigsmal ( The Lay of Rig ) it clearly states that Heimdall is Rig. Also in Voluspa if memory serves me correctly Heimdall is called the Father of Man. Yes ! The line is "Greater and lesser, kinsmen of Heimdall."
The book overall is mediocre, but that one line, if read by a novice, could shape their views, or I guess a better way to put it would be inaccurate views, for a lifetime. If the author had said that the Rigsmal said it was Heimdall, but that he personally believed that it was Odin I could at least accept it, though he would still be wrong. But when a Ph. D. makes a bold statement like that it tends to be believed by those who do not know any better.
I did find this statement on Wikipedia so I thought I would share . "However, some scholars, including Finnur Jónsson and Rudolf Simek, have suggested this is a role more appropriate to Óðinn and that the Eddic tradition has thus transferred the name Rígr from him to Heimdall." My question is how can any " scholar " transfer what was written just because they " believe " that the " Eddic tradition " is wrong ? Show me another original version of the Eddas with Odin as Rig and I will change my opinion. Until then I will accept what those who wrote the Eddas have told us !