Brighton & Hove Albion pair Liam Rosenior and Kazenga LuaLua will both be out for the rest of the month.
Full-back Rosenior, 31, has a medial knee injury, while striker LuaLua, 24, has had minor groin surgery.
The surgery has set back LuaLua's expected comeback by a month, who has not played since 19 September.
"Liam is someone that is very versatile. He came as a right-back who could cover other places," coach Nathan Jones told BBC Sussex.
The Seagulls remain unbeaten this season and sit top of the Championship table ahead of Saturday's home match against Charlton.
"Liam has been performing well," said Jones. "He has covered at left-back and done fantastically well. It's frustrating because he's a key member of our squad and also our 11 and he's been in very good form.
"We're happy with the depth we have. We'd like everyone to be fit to have even more options, but that's just coaches being greedy."