Republic of Ireland boss Giovanni Trapattoni faces an anxious wait as three of his players prepare to undergo scans on Monday.
Key midfielder Glenn Whelan damaged a hamstring 20 minutes into Stoke's 0-0 Barclays Premier League draw with Liverpool and will be assessed when he meets up with the squad in Dublin.
He joins Leicester defender Sean St Ledger and Sunderland winger James McClean on the injured list with striker Kevin Doyle having already been ruled out with a thigh problem.
St Ledger will also have a scan on his hamstring in Ireland, while McClean's groin will be examined on Wearside after he complained of tightness following the 3-0 defeat at Manchester City.
Manchester United winger Robbie Brady, who was initially placed on the stand-by list, has already been drafted into the squad along with Sunderland's David Meyler.
The Republic face Group C favourites Germany at the Aviva Stadium on Friday evening and then head for Torshavn for the clash with the Faroes next Tuesday.
They launched their qualification campaign with an unconvincing 2-1 win in Kazakhstan last month, but will be looking for a significant improvement this time around.