Trimble centre stage for Glasgow clash
Trimble, who started out as a centre before reverting to the flanks last season, looks certain to replace Kevin Maggs and also fill the hole originally left by Paddy Wallace who will be utilised to play fly-half in the absence of the injured David Humphreys.
Ulster coach Mark McCall, however, is also awaiting a fitness report on full-back Bryn Cunningham who missed the defeat by Leinster last weekend due to a back injury. If Cunningham fails to come through then Mark Bartholomeusz will continue at full-back with youngster Paul McKenzie on the left wing.