Captain Johann Muller has been ruled out of their of Ulster’s back-to-back Heineken Cup Pool 4 clash with Northampton at Ravenhill on Saturday, 6.00pm.

Muller is sidelined with a displaced fracture in his arm so 20-year-old Iain Henderson has moved into the second row alongside Dan Tuohy.

Nick Williams has been promoted from the bench to fill the vacant loose forward spot, while Chris Henry will captain the side who are looking to maintain their impressive unbeaten streak, most recently beating the Saints 25-6 at Franklin’s Gardens last Friday.

Andrew Trimble will make his 50th Heineken Cup appearance, following in the footsteps of Paddy Wallace and Tommy Bowe, who recently reached the half-century milestone.

There is only one change on the bench which sees Neil McComb replace Williams, while Ricky Lutton will make his European debut if he takes to the field at any time during Friday’s game.

The 26-year-old development prop has made one previous appearance when he came on as a substitute in the RaboDirect PRO12 win over Edinburgh last month.

Ulster XV v Northampton Saints, Saturday, Ravenhill, 6.00pm: J Payne; T Bowe, D Cave, P Wallace, A Trimble; P Jackson, R Pienaar; T Court, R Best, J Afoa, I Henderson, D Tuohy, N Williams, C Henry (capt), R Wilson.

Replacements: N Brady, C Black, R Lutton, N McComb, R Diack, P Marshall, L Marshall, C Gilroy.

There will be full live coverage of Saracens v Munster on Sunday Sport on RTÉ Radio 1 on Sunday 16 December from 2pm.

There will be full live coverage of Biarritz v Connacht on a specially extended Sport at Seven on RTÉ Radio 1 on Friday 14 December from 7pm.