All or nothing.

Robbie Diack, Callum Black and Charles Piutau will play their final games in Ulster colours after being named in the starting team for Sunday’s crunch Champions Cup play-off versus Ospreys.

The coaching team have been boosted by the return of John Cooney and Piutau, who missed the Guinness PRO14 trip to Munster earlier this month due to concussion and personal reasons respectively.

However, Rory Best (hamstring), Iain Henderson and Clive Ross (both knee) have been ruled out through injury, so Rob Herring, Kieran Treadwell and Diack come into the side.That means that there are five personnel changes to the starting XV that drew 24-24 at Thomond Park.

John Cooney will start at scrumhalf and he will resume his half back combination with Johnny McPhillips, who will start for the ninth consecutive game.

Piutau’s inclusion at fullback sees Louis Ludik switch to the right wing berth, with Jacob Stockdale named on the other flank. Stuart McCloskey and Luke Marshall will form a familiar partnership in midfield.

Diack, who is set to earn his 206th Ulster cap on Sunday, will be joined in the back row by Sean Reidy and Nick Timoney.

With Best out injured, Herring comes in to start at hooker and will also take over the captaincy role. Callum Black and Ross Kane will pack down either side of their skipper, while Alan O’Connor and Treadwell are paired in the second row.

Abbey Insurance Academy lock Jack Regan* could make his senior debut after being named among the replacements. Fellow Academy player Tom O’Toole, hooker John Andrew, prop Andy Warwick and back row Chris Henry are also included on the bench. Dave Shanahan, Darren Cave and Craig Gilroy are the additional backline options.

Ulster Rugby team to play Ospreys

(15-9): C Piutau; L Ludik, L Marshall, S McCloskey, J Stockdale, J McPhillips, J Cooney;
(1-8): C Black, R Herring (captain), R Kane, A O’Connor, K Treadwell, R Diack, S Reidy, N Timoney;

Replacements: (16-23): J Andrew, A Warwick, T O’Toole, J Regan, C Henry, D Shanahan, D Cave, C Gilroy.