SYDNEY'S low-scoring loss to Richmond has been compounded by potentially serious injuries to co-captain Josh Kennedy and star forward Isaac Heeney.

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Gun midfielder Kennedy had his knee heavily iced up late in the first quarter after twisting awkwardly while tackling Tiger opponent Marlion Pickett.

"Josh has done a medial, so he'll miss a number of weeks. It was pretty bad," Sydney coach John Longmire said following the match.

The Swans were then hit with another blow when star forward Isaac Heeney hobbled off with an ankle injury late in the match, which Longmire also labelled "pretty bad".

Heeney's injury is still being assessed and its severity is not yet known.

The Swans' line-up had already had a shake-up ahead of the first bounce when key defender Aliir Aliir was replaced by Robbie Fox. 

"He just hadn't been playing very well, he hadn't been playing to the standard that he likes to," Longmire said of Aliir.

When questioned after the low-scoring match about his tactics in defence, Longmire said he didn't play Callum Mills as a spare man down back, preferring to use only six defenders, but Richmond coach Damien Hardwick was frustrated with the way Sydney shut down the game.

"I think we had 50-odd inside 50s for what, four or five goals, which is farcical in nature really. Horrible game of football," Hardwick said.

When questioned about how the Tigers could have opened up the game, Hardwick said: "There's not much I can do, we're attacking, we've got 75,000 people in our forward 50 so it's pretty hard."

"It's become a tactic in the AFL, fold-back mentality is really keeping sides in games at the moment and it's creating the game that we got tonight."

The Tigers won't regain captain Trent Cotchin this week, but there's some positive news at the selection table for Richmond.

"Not this week, he (Cotchin) won't be available, but possibly the following week. Dave Astbury trained well today so he'd come into calculations."