Striker Saido Berahino's loan spell with Peterborough is over after he suffered a chipped bone in his knee.
The 19-year-old, who was on loan from West Brom until 2 January, was injured in last month's 1-1 draw at Ipswich.
Posh manager Darren Ferguson confirmed that the England Under-20 international would be out for at least eight weeks.
"It's part and parcel of the game but it leaves us very light (in attack), there's no question about that," Ferguson told BBC Radio Cambridgeshire.
Berahino made 10 appearances for the London Road club, seven of them starts, and scored twice in a 3-0 victory over Derby County in October.
However, Peterborough are bottom of the Championship table with just 13 points from 20 matches and Ferguson will have to wait until the transfer window reopens next month before he can strengthen his squad as neither Tyrone Barnett nor Emile Sinclair can be recalled from loan spells with Ipswich and Barnsley,
He said that once Berahino regains full fitness, he would like to try and negotiate a new loan deal with West Brom.
"I think the ones we've brought in on loan this season, Saido and George Thorne, have made a difference. They've done really well.
"They're two good players and two we'd like to extend, definitely, if we can," Ferguson added.