New coach Craig McRae revealed after Wednesday's training that Hoskin-Elliott and assistants Brendon Bolton and Josh Fraser are all isolating at home.
They will miss Friday night's round-one game against the Saints at Marvel Stadium.
It's been a bad week for Hoskin-Elliott, after he was hurt at training on Monday when he landed awkwardly.
McRae said they were confident the forward would prove his fitness for Friday night, but COVID-19 has made that a moot point.
"We thought he might have to prove his fitness today, but he's now been put on Covid protocols, he's going to be out for seven days as a minimum," McRae said.
"Two of our coaches are going to be out of the game as well, which is just part and parcel of the environment we're in, isn't it.
"They (Bolton and Fraser) can still prepare from home and players have been well-prepared to play.
"He (Hoskin-Elliott) was ready to prove his fitness ... the physios and the like were confident he was going to get through."
Player Will Kelly also missed training, but McRae said he has a bout of gastro.
All 18 clubs have top-up players available this season in anticipation of COVID-19 continuing to affect the league.
But the AFL is adamant that the season will go ahead as scheduled.
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