Shane Long has been left out of the Republic of Ireland squad for the World Cup qualifier against Austria this month.
The 29-year-old striker injured a hamstring in Southampton's Europa League defeat to Inter last week and will not be risked for the game in Vienna on November 12.
There are concerns over the fitness of John O'Shea, Stephen Ward and James McCarthy, who are among the players who will be assessed by Ireland medical staff next Monday.
Martin O'Neill has handed debut call-ups to Daryl Horgan and Andy Boyle, who have impressed in Dundalk's Europa League campaign after having helped the club to regain their domestic title.
"The report coming from Southampton is that it will be too early for him," O'Neill told a news conference when asked about Long.
"If the game was this week then James McCarthy would be out. He is doubtful for the week after.
"I've been impressed by the way Dundalk play. Quite a number have done well. Any players who are called up deserve to be."
Defenders: Seamus Coleman (Everton), Cyrus Christie, Richard Keogh, Alex Pearce (Derby County), John O'Shea (Sunderland), Ciaran Clark (Newcastle United), Paul McShane (Reading), Shane Duffy (Brighton and Hove Albion), Andy Boyle (Dundalk), Stephen Ward (Burnley)
Midfielders: Aiden McGeady (Preston North End*), James McClean (West Bromwich Albion), Jeff Hendrick (Burnley), James McCarthy (Everton), Stephen Quinn (Reading), Glenn Whelan (Stoke City), Harry Arter (Bournemouth), Eunan O'Kane (Leeds United), David Meyler (Hull City), Stephen Gleeson (Birmingham City), Conor Hourihane (Barnsley), Robbie Brady, Wes Hoolahan (Norwich City), Callum O'Dowda (Bristol City), Jonathan Hayes (Aberdeen), Daryl Horgan (Dundalk)
