Southampton manager Ronald Koeman expects striker Charlie Austin to be sidelined for "several weeks" with a hamstring injury.
Austin, 26, was substituted in the 60th minute of Southampton's 2-0 loss at Bournemouth in the Premier League on Tuesday.
"For sure Charlie is a hamstring injury, [that's] what I heard from the doctor," Koeman, who also had to replace Shane Long on 70 minutes, said on the club's official website.
"Shane was a kick on his knee and I think that's not so bad, but I think Charlie will be out for several weeks."
Austin signed for Southampton from Queens Park Rangers in January and he has scored once in five league games since the move.
The Saints' defeat leaves them seventh in the table, three points behind West Ham whose game in hand is against Tottenham on Wednesday.