Roberton copped a knock to the head in the second quarter of the Saints' five-point loss to Port Adelaide at Etihad Stadium and was cleared to come back on.
He then appeared dazed in a pre-arranged half-time interview with the Seven Network's Cameron Ling, during which he said he wasn't sure where he was.
He was subbed out at half-time.
AFL spokesman Patrick Keane said the League spoke to the Saints on Sunday and was confident the club had followed acceptable concussion treatment proceedures.
"Football operations spoke to the club yesterday as all head knocks are followed up as a matter of course," Keane told AFL.com.au.
"Basically we are happy with the explanation provided."
Roberton appeared fine when first tested for concussion but then suffered delayed symptoms, which was confirmed by captain Nick Riewoldt on Sunday.
"Concussion is difficult to determine," Riewoldt told Channel Seven's Game Day.
"Our medical staff went out to Dylan and he seemed fine at the time but with concussion there can be a delay of the symptoms.
"He was assessed at half-time and it was clear that he was in no fit state to continue.
"The doctors had his best interests at heart the whole time. If there were any grey areas at all they would have brought him off."
Jennifer Phelan is a reporter for AFL Media. Follow her on Twitter @AFL_JenPhelan.