Mark McCall is undecided on three of his starting lineup for this local derby on Stephen's Day. David Humphreys and Paddy Wallace are in contention for the fly-half berth, while either Rory Best or Paul Shields will play at hooker while Justin Harrison's partner at lock is between Matt McCullough and Tim Barker. Connacht make 6 changes for the trip to Belfast with David Gannon, Ray Ofisa, Colm Rigney, Chris Keane and Darren Yapp all coming into the side. Ulster: B Cunningham, M Bartholomeusz, P Steinmetz, K Maggs, A Trimble, D Humphreys/Paddy Wallace, K Campbell, J Fitzpatrick, P Shields/R Best, S Best (cpt), J Harrison, M McCullough/T Barker, N Best, N McMillan, R Wilson. Replacements: P Shields/R Best, B Young, M McCullough/T Barker, K Dawson, I Boss, D Humphreys/P Wallace, T Bowe. Connacht: D Riordan, D Yapp, P Warwick, G Williams, K Matthews, Mark McHugh, Chris Keane, Brett Wilkinson, John Fogarty Â©, S Knoop, D Gannon, A Farley, J Muldoon, R Ofisa, C Rigney. Replacements: A Flavin, B Sturgess, M Swift, M Lacey, C O'Loughlin, J Hearty, T Robinson.