The AFL confirmed on Monday umpires had not raised any concerns, and it was simply an on-field matter.
It's understood Collingwood has no issue with O'Brien's behaviour either, and supported the defender's move to publicly clarify the matter.
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A television viewer watching Saturday night's Collingwood-Geelong game took to Twitter, alleging O'Brien called Hawkins a "f***ing f**got". The post was widely re-tweeted and reported.
On Sunday, O'Brien denied he'd used a homophobic slur, but admitted he did direct a spray towards Hawkins.
"Just to clear something up..Id never resort to a homophobic slur..for those wanting to know, I said fat f$@k..simply some onfield banter," O'Brien tweeted to his 44,000 followers.
He continued: "there was a lot of passion in that game & things did get heated...there was 2 way banter...Just what you expect in the heat of the battle."
Last season St Kilda forward Stephen Milne received a $3000 fine from the AFL for directing a homophobic slur at O'Brien.
Matt Thompson is a reporter for AFL Media. Follow him on Twitter @MattThompsonAFL
