Charlie Austin could be set for an extended spell on the sidelines if his suspected dislocated shoulder has caused lasting damage.
Southampton crashed out of the Europa League to Israeli minnows Hapoel Be'er Sheva in a toothless display in Thursday night's 1-1 draw at St Mary's.
The south coast club's lacklustre situation then took another turn for the worse with injury to nine-goal leading scorer Austin, who will miss at least Sunday's Premier League clash with Middlesbrough.
Saints boss Claude Puel admitted he does not know how long Austin will be sidelined, and will sweat on the outcomes of tests on Friday.