Fremantle released a photo of the disguises described by development coach Steve Malaxos as "sort of Ku Klux Klan outfits".
The two players were wearing white sheets cut off at the neck, white masks, sunglasses, hats and a scarf.
"The facts are, two of our younger players have played a private, non-discriminatory, harmless practical joke on four of their teammates," Rosich said on Tuesday afternoon.
"They've egged – and in one case 'glad-wrapped' – their teammates' cars and then taken photos of themselves wearing disguises that included a cut-off sheet, mask, hat, sunglasses and scarf.
"Once you've seen the photo, I'm sure you will agree that Stephen's description was inaccurate."
Rosich said no rift in the player group had been caused by the pranks, which took place on four separate occasions, and none of the players would be sanctioned.
There were no indigenous players involved.
Rosich and football manager Chris Bond spoke with the entire Fremantle list on Tuesday, and the CEO said there was no rift between players as a result of the pranks.
"I spoke with Des Headland and Antoni Grover, who are in our leadership group," he said.
"They see the light-hearted nature in the matter that's taken place and have absolutely no issues with the two players concerned at all."
Development coach Malaxos made the comments on Perth radio station Sports FM on Saturday morning.
In a conversation about football club pranks, Malaxos first described a prank in which players had altered a training program to include a 3km time trial, fooling several coaches.
“There’s a reasonable amount of pranks that go on all the time,” Malaxos then continued. “Sometimes they raid each others’ houses in sort of Ku Klux Klan outfits.
“That’s one of the other pranks.”
Rosich said Malaxos made an error of judgment on radio.
"We have spoken to Steven a number of times this morning. He regrets those comments, he agrees they were inaccurate and he doesn't know why he said it," Rosich said.
The Ku Klux Klan is a notorious white supremacist group with a history of violence, primarily towards African-Americans and Jews.
