The Latics have taken Tyias Browning on a short-term deal from Everton - bolstering their defensive options.
Rosler has also been able to move striker Grant Holt out to Aston Villa, freeing up space and funds for new recruits.
He admits that he would like to bring in another couple of fresh faces, with Cardiff City forward Nicky Maynard set to be one of those.
Rosler said in the Wigan Evening Post: "There will be more players coming in during January, but they will be loanees.
"I have made some room on the wage bill, and you will maybe see two more players leaving on loan to make some more room.
"I would expect two more players to come in, both of them on loan. I cannot buy anyone, the money has been spent.
"What I can do is create some room on the wage bill so I can bring in players this way, and that is what I have done."
While a deal for Maynard is imminent, Rosler concedes that strengthening at the back remains a top priority.
He added: "The headache I have is in defence, because we have got too many players out of action.
"It was an experimental selection on Tuesday night (against MK Dons), but it had to be like that.
"We had three established centre-backs injured and two younger defenders cup-tied.
"Gary (Caldwell) has been out long-term, Ivan (Ramis) has come back but got re-injured, Thomas (Rogne) is injured, and it is a credit to the squad that we are continuing to pick up results."