Injuries and Six Nations calls have left Ulster's resources sorely stretched ahead of Friday night's PRO12 date with Ospreys (7.05pm).
Yesterday's announcement of a 25-man extended squad confirmed that, with only two members to be culled tomorrow.
Those 25 include Darren Cave and Andrew Trimble, though they could yet be required by Ireland depending on the injury situation at Carton House. Ulster coach Mark Anscombe will know the score on that one later today.
He explained: "If we have them, we have 16 unavailable for this weekend. If we don't, we'll have 18 missing."
In the circumstances, Ulster have called up 21-year-old Ballymena prop Andrew Warwick, who has never had a game for the province's seniors.
Anscombe said: "When you start going through the names of the guys who are missing you see the size of the problem; Paddy McAllister, Adam Macklin, Chris Farrell, Roger Wilson, Stephen Ferris, Tommy Bowe, Nick Williams, Jared Payne and Adam D'Arcy are injured and John Afoa is away (in New Zealand).
"Then you add the international players (Rory Best, Craig Gilroy, Chris Henry, Declan Fitzpatrick, Iain Henderson and Paddy Jackson) and that's 16.
"The injuries we've had have been serious. We have had three guys out for the season. First there was McAllister, then it was Farrell and then Macklin."
Asked about the likelihood of Bowe playing again this season, he said: "If you'd asked me that question a month ago I would have said no. But he was in the gym yesterday and he's in good spirits so who knows?
"The (Heineken Cup) quarter-final may be a bit early but if we can hang in there, who knows? We could see him."
Ferris is "closer" to a return, the coach revealed. "Fingers crossed, end of this month, maybe. Glasgow? Treviso? We'll see."
But Anscombe confirmed that Ulster are unlikely to have Williams, Wilson or Payne for any of the next four matches against Ospreys (h), Zebre (h), Glasgow (a) and Treviso (h).
"That's a pretty influential group to have missing," the Kiwi admitted.
On the plus side he can include fit-again captain Johann Muller, fellow-lock Dan Tuohy and centre Luke Marshall for Friday's game with the defending champions.