Swann stunned the cricket world with his announcement on Sunday that he was immediately resigning from the England team midway through the Ashes series and stoked tensions by saying some players had "no idea how far up their own backsides they are". (Agencies)
There was speculation he was referring to his England colleagues, particularly outspoken batsman Kevin Pietersen. But Swann has since denied that and Cook said on Wednesday he had insisted it was not the case.
"A phone call to Swanny reassured me very quickly that it wasn't at all anything about England players," Cook told reporters ahead of Thursday's Boxing Day fourth Test, where the tourists will be hoping to stave off a 5-0 whitewash of the series.
"I haven't heard the quotes exactly -- obviously I've seen what's been written -- and whether it's come across badly, he totally 100 percent reassures me and the whole England team that it's not about us.”
"So to me the matter's closed on that."
Australia clinched the Ashes by taking an unbeatable 3-0 lead in Perth and Swanns's departure has further destabilized the tourists' already-shaky campaign.
But Cook commended Swann for his courage, saying "no one's forcing you to play cricket for England, we're privileged to do that."
"Graeme just gave up a lot for that England shirt and he had no more to give, and I think it's a very brave decision," he said.
"He could have just hung on for these two games, and whether he played or not is pretty irrelevant, he could have stayed but he was like 'I know I've got no more to give, I don't feel I've got anything left'."
Cook said Swann "will be missed because he was a fine, fine cricketer."
Swann stunned the cricket world with his announcement on Sunday that he was immediately resigning from the England team midway through the Ashes series and stoked tensions by saying some players had "no idea how far up their own backsides they are".