Southampton manager Mauricio Pochettino admits it is "difficult to analyse" how long his team must do without goalkeeper Artur Boruc because of a broken hand.
The 33-year-old suffered the injury during the 3-1 Barclays Premier League defeat at Chelsea on Sunday.
Given the hectic festive schedule, Boruc could miss some eight matches if he needed a six-week recovery time.
Reserve Kelvin Davis is also sidelined, so Argentine Paulo Gazzaniga looks set to step in for the visit of Aston Villa on Wednesday.
"It is difficult to analyse how many weeks Artur will be out for," Pochettino said at a press conference reported on the club's official Twitter feed.
French midfielder Morgan Schneiderlin will miss out because of a groin injury picked up on Sunday and Gaston Ramirez is also not yet match fit.
Southampton will be looking for a response after successive away defeats to Arsenal and Chelsea, which has seen them drop out of the top four.
Pochettino said: "We don't have time to dwell on our two consecutive defeats because we are only thinking about tomorrow's game.
"We have lost on two very difficult grounds at Arsenal and Chelsea, so now we will try to impose our values and get the win over Aston Villa.
"I am expecting a physical game.
"Aston Villa are a strong side and very good on the counter-attack, especially away from home."