SYDNEY coach Dean Cox has acknowledged a mounting injury list has created open positions in the senior line-up as the Swans head into the second half of the season.

The squeeze comes as Sydney captain Callum Mills remains in doubt for the clash against Richmond on Saturday after leaving the track early on Thursday, failing to complete the session just two days out from the game.

Malcolm Rosas jnr will be sidelined for one to two weeks after rolling his ankle against Geelong, while Tom Papley faces a six-week stint on the sidelines because of a calf injury sustained in the same match.

Speaking on Thursday, Cox balanced bad news with good on his small forwards.

"Obviously disappointed, especially Tom, to hear that you're out for a little bit of footy. It's news you never want to receive," he said.

"So, we'll work our way through that with Tom. Malcolm's (injury) was better news than probably what we expected straight after the game. He won't be available this week, but we'll see how he goes next week or the week after."

The latest injuries add to those to Matt Roberts and Dane Rampe, while Errol Gulden is not expected back until after the mid-season bye.

When questioned about managing Brodie Grundy’s workload after a demanding game against Geelong, Cox said that while mid-season soreness is common across the competition, Grundy is feeling good and preparing to play against the Tigers.

Should Grundy require a rest at some stage, Cox expressed full confidence in VFL ruck Peter Ladhams to step up, adding there's a possibility of playing both rucks in the same side at some stage.

Similarly, the selection committee is discussing whether to recall forward Hayden McLean to form a four-tall forward line, although Cox noted that his existing key forwards were not the issue in last week's loss to Geelong.

Cox admitted after the loss to the Cats that he'd erred in dropping James Jordon's tag on Bailey Smith at half-time, a move he made due to Geelong's midfield dominance.

The attempt to fix the engine room involved moving James Rowbottom back into the midfield from the forward group and shifting Logan McDonald onto Tom Stewart to neutralise his influence, but neither strategy could stop the Cats' flow.

"One thing we always looked at through that period was how our midfield group was going as a whole," Cox said.

"One player doesn't make that midfield group. I think with the ability to try and get some extra numbers in there, we threw (James) Rowbottom in there at the start of the third (term) off Stewart and put Logan onto Stewart.

"There were some things, and it just didn't work ... towards the back end, we tightened up on (Smith) and he still got the ball and kicked a goal when 'JJ' (Jordon) was on him. Unfortunately, the momentum was too great."

While the tactical move couldn't stop Smith, it did spark a contested possession turnaround, with Sydney swinging the count to +10 in the second half as the Swans fought back to win the third quarter 33-27. Ultimately, however, Cox admitted his coaching moves failed to counter the opposition's heavy tagging of Isaac Heeney or resolve the team's broader ground-ball struggles.

"We thought if Isaac's getting sat on, and then you're tagging another one, how do you balance the contest? Because we were -26 in ground balls in the first half," he said.

"There are always areas you look at. This was one that I didn't get right, and there's going to be plenty more of them throughout my career, no doubt."

Beyond the clearances, the Swans have also suffered from a negative turnover differential against both Geelong and Collingwood, though they still managed to secure a victory over the Magpies the week prior.

Cox emphasised Sydney must improve across all phases of its game, not just turnovers, but said his coaches are refining how they defend turnovers, where they create them, and how they launch their counterattacks.

"It's an area of our game where we've gone from the best to not being efficient at it. On the weekend, with the turnovers, we just didn't create enough of them either," he said.

"That was a real strength of ours for the first seven or eight games, and it's probably something that we're looking at: how do we create more of those? It's not just about the score, it's about the total number as well before we can try and be potent off the end of it."