Dermott first had problems with the elbow on last summer's Australasian tour and has now dislocated it twice this season. He is definitely out of tomorrow's league game against Wakefield Trinity and is most unlikely to be fit in time for the Cup on the weekend of 13-14 February.
That gives an early chance to the former Rochdale hooker, Martin Hall, signed, with remarkable foresight, just before the Challenge Cup deadline last month. During Dermott's absences this season, the Wigan coach, John Monie, used non-specialists, Mick Cassidy, Martin Crompton and, on Sunday, Jason Robinson in the role.
'But Hall was signed as back-up hooker and has to be given his chance, even though I've only seen him a couple of times in the A team,' Monie said.
Phil Clarke is doubtful tomorrow with a leg strain, but Martin Offiah and Denis Betts will be back, while Wakefield will be without their Australian forward, Darren Fritz, who has returned to Canberra after an outstanding stint with the club.
Wigan, Challenge Cup winners for the last five years, have already lost twice to Saints this season, including a 41-6 humiliation at Knowsley Road on Boxing Day. Their tie is the obvious choice as the televised Saturday match on 13 February.
Elsewhere, the draw has been kind to the more fancied sides, with only two other ties between First Division opponents, Bradford going to Wakefield and Widnes to Sheffield.
Last year's beaten finalists, Castleford, have what looks like a comfortable home draw against Hunslet, while Leeds, who have started to fulfill their expensive potential over the last few weeks, have Rochdale Hornets at home.
That was a draw with which their coach, Doug Laughton, declared himself well pleased, especially as he knows that at least one of the main threats is bound to be eliminated at Central Park.
SILK CUT CHALLENGE CUP Second-round draw: Hull Kingston Rovers v Keighley; Halifax v Batley; Oldham v Huddersfield; Wakefield Trinity v Bradford Northern; Leeds v Rochdale Hornets; Wigan v St Helens; Sheffield Eagles v Widnes; Castleford v Hunslet. Ties to be played 13 and 14 February.