Walcott is pushing to play centrally for club and country.
"I don't understand this whole idea of Theo Walcott playing up front," Barnes told talkSPORT. "Theo has been scoring goals from a wide position, [so it doesn't make any sense].
"Frank Lampard, and David Platt before him, got goals regularly but they didn't say, 'because we score, we want to play up front'.
"Theo has to understand that his best position is coming in from the wide areas, where he can still score his goals."