The Saints have provided an injury update following their Round 16 victory over the West Coast Eagles at Optus Stadium, with mixed news emerging on Monday regarding a host of senior players.
During Sunday afternoon's bout with the Eagles, running wingman Bradley Hill and veteran midfielder Seb Ross each suffered knee injuries, while key defender Josh Battle was substituted out of the game early after falling victim to a concussion.
There was also unfortunate fallout from St Kilda's VFL affiliate, Sandringham, after its heavy defeat at the hands of Werribee on the weekend, with defender Daniel McKenzie and midfielder Jack Bytel succumbing to fresh injuries.
It is believed the luckless McKenzie has suffered a new calf strain, while Bytel fell victim to an abdominal complaint that could sideline him.
St Kilda's acting football boss, David Misson, first commented on the imminent return to play for the promising Hayes, who has been recovering from burdensome ACL and foot concerns.
"As long as he gets through training this week, Jack should play," Misson said.
"He's done the hard work and, whether it's this week or next week, we're looking forward to seeing that effort rewarded."
Hill and Ross, meanwhile, were visibly plagued by their respective knee ailments during Sunday's win, and while they played out the contest, both will undergo scans to determine the severity of their injuries.
"We don't know the severity of Bradley and Seb's injuries yet, so we'll await the scan results before attempting to put a timeline on them," Misson stated.
Particularly disappointing is the news regarding McKenzie, who was only recently cleared to make his long-awaited return to play with the Zebras.
"Similarly to Bradley (Hill) and Seb (Ross), we'll wait for the boys' scans to come back before looking at a return-to-play date for Dan and Jack," said Misson.
Finally, Misson revealed that Clark's timeframe for return is similar to Hayes'.
"We'll just have to see how the week plays out with Hunter," Misson continued.
"It might be this week or he may need another week, he's an important player and we won't rush him back."
While Misson didn't comment on the condition of Battle, the defender is listed as 'TBC' on the Saints' official injury list following Round 16's action.