SYDNEY is expecting star Isaac Heeney to miss up to a month of footy after the gun forward broke his hand in the thrilling three-point win over Essendon.

Heeney started the game brightly, until he was seen grimacing and nursing his right hand as he made his way from the field early in the second quarter. He went straight down to the rooms for treatment.

The bad news was confirmed when medical substitute James Bell entered the game just minutes later, and when Heeney returned to the bench after half-time with his hand wrapped in ice. 

"It's just terrible luck for him. He's one of our best preparers, he trains so hard," Sydney coach John Longmire said.

"He's got a crack in his hand, so it's three weeks or four weeks, I guess. [But] I'm not sure what the official diagnosis is.

"What Isaac is, is a really positive person. So he'll get over the disappointment of tonight and get to work and get himself right."

Heeney managed only six games in 2020 until a serious ankle injury ended his season. 

There was concern early in the pre-season that the injury might force the 24-year-old to miss the start of 2021 too, or at least enter it underdone. But he was quickly back to his best and kicked eight goals in the first three matches. 

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"He's worked so hard to come back from his ankle," Longmire said.

"He's been in great form for us this year, and a really important forward."

Essendon coach Ben Rutten couldn't hide his disappointment with the result, but said that he was "proud of the group".

The Bombers are the first team to push Sydney for four quarters this season, and the Essendon coach revealed part of their plan for stopping one of the most exciting and in-form teams in the competition.

"A big part of their game is being able to get the marks and being able to use the ball by foot, so we tried to be really tight on the defence. I think we did that pretty well," he said.

"The main focus of today was that it was a tight, high pressure game."

The Bombers' defence was able to mostly keep Lance Franklin out of the game after half-time, but the Sydney superstar bobbed up to kick his third goal late in the final quarter to stretch the margin beyond one goal. 

Franklin's long-time rival, Cale Hooker, spent the night at the opposite end of the field, and kicked his own third goal as the final major of the game, but it was too late for the Bombers.

"It was very much a team effort to be able to quell 'Buddy'," Rutten said. 

"But Buddy can do some things, and he's been doing that for a long time. He's hard to stop for the whole game."