Leyton Orient have lost both John Mackie and Shane Tudor after they underwent operations.
Mackie went under the knife to clear up a long standing foot problem while Tudor has his tonsils removed.
Mackie is expected to be sidelined for six weeks, but Tudor should be back sooner than that.
"Both Johnny and Shane have had their operations and they went successfully," said manager Martin Ling.
"John's foot showed a little more trauma than we'd expected because he's had to play through his injury recently, but we'd still expect him back within six weeks.
"Shane will be back well before that and I look forward to having both players back fully fit and ready to go."
Meanwhile, the club have extended the loan of Charlton striker James Walker for an additional six weeks.
"I'm really pleased that we've managed to extend James's loan from Charlton," added Ling.
"He's had an excellent impact since arriving here at the end of November and I'm sure he will continue to flourish over the next seven weeks."