Ulster Coach Brian McLaughlin has concerns over the fitness of both Paddy Wallace and Willie Faloon ahead of Friday's game with the Ospreys at Ravenhill.
Faloon took a knock to the shoulder in the win over Munster and Wallace turned over his ankle on the hard surface at Ravenhill.
McLaughlin has named an extended 28 man squad ahead of the clash.
"We have to make sure we are up for the game, we have to compete and we have to make sure we beat them at Ravenhill. We have to go to town with them up front and we have to show that we are more than capable of dealing with them," he said.
"Ospreys are a dangerous side, who can and do compete at the highest level, we need to ensure we give them nothing to play with.
"At training this week we will work hard in certain areas of the pitch, the focus will be to put down our patterns of play, after that, on the day, it's just a matter of us holding onto the ball and making the best use of any chances we have. We must put them under pressure.
"It's vital for our Magners League campaign that we win our home games and build a solid platform from them."
Only six points separate Ulster from Ospreys, on an extremely tight and competitive Magners League table.
The Ospreys manager Jon Humphreys had admitted that they may not field an overly strong team for the match.
Ulster's starting 22 will be named on Thursday.
There will be a pitch inspection at Ravenhill on Wednesday morning to determine if Friday night's game will go ahead.
Ulster Squad Forwards:
Declan Fitzpatrick, Bryan Young, BJ Botha, Nigel Brady, Andy Kyriacou, Ed O'Donoghue, Dan Tuohy, Ryan Caldwell, Chris Henry, Tom Court, Stephen Ferris, Willie Faloon, TJ Anderson, Neil McComb, David Pollock
Ulster Squad Backs:
Jamie Smith, Clinton Schifcofske, Simon Danielli, Darren Cave, Ian Whitten, Timoci Nagusa, Ian Humphreys, Niall O'Connor, Isaac Boss, Paddy Wallace, Andrew Trimble, Cillian Willis, Jonny Shiells
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