The Saints lost Rhys Stanley (collarbone), Tom Simpkin (leg) and Arryn Siposs (shoulder) this week to season-ending injuries, while Sam Fisher (foot) is already done for the year.
Sam Gilbert (knee) is close to playing while James Gwilt (knee) is rated a chance only.
With other tall options Beau Maister (hamstring) and Justin Koschitzke (calf) also unavailable, Watters highlighted how the depth of the list had been affected by salary cap pressure that squeezed out players such as Zac Dawson in 2011.
But he said the club was poised to make some big changes this off-season.
"There's something about blokes at this club over six foot one, if you look at the year and where our injuries have occurred," Watters said.
"It says a lot about if you go back a couple of years - I don't think people fully realise the salary cap pressure this club was under.
"What I can say to our supporters is we now have our salary cap in a very aggressive position - probably for the first time in 24 months it's in an offensive position and we intend to make some additions to this club at the end of the year.
"Whist this week with some injuries to our key defenders, no doubt it's going to be a challenge, we're not a club that wants to sit on our hands.
"We need to improve in that area and we've got ourselves in a position to do that."
Koschitzke didn't train on Thursday at Seaford and Watters said he was "still tracking" in his rehab but not available this week.
The veteran remains on 199 games and wants to reach his 200th milestone before his likely retirement.
"He's had no setbacks but he's not available to play at this point," Watters said.
"If he gets cleared and he plays well, he's a chance to play."
Watters added there was "always a balance" in giving games to players who may not have earned a place.
He said the Saints would like to see Koschitzke get to his milestone but they had to wait and see how the next four weeks panned out.
"You can definitively make a statement about offering milestone games and you need to maintain a level of integrity about selection," he said.
"At the same time you need to show respect to players who have given not just effort over 10 to 15 years - they've put their body on the line for a football club.
"So rewarding that type of player also builds culture. We'll have young players who are zero to 15 games into their career and they're watching how we treat someone who has been here for 10 to 15 years and so they should.
"I have gone on the record to say it needs to be earned and I stand by that, but I would also love to see him get to 200 games.
"I think it would be terrific for him and the football club. We just have to see how the next few weeks pan out."
Ahmed Saad, who is waiting for the revelations of his B sample drug test after testing positive to a prohibited drug, did not train on Thursday.
Watters declined to discuss Saad's situation.
"There was a fair bit said last week and I think it was covered pretty well," he said.
"We're here to play football now."
Gwilt and Maister trained, and Watters said it appeared as though the players and coaches had emerged from the bout of gastro that swept through the club late last week and early this week.
