Rosler is expected to have a large amount of James McCarthy's £15million summer transfer fee at his disposal, but he insists he must assess his current side and choose who he wants wisely before splashing the cash.
Brentford just missed out on automatic promotion last season in a thrilling final game, before missing out in the play-offs.
Rosler hopes to use his experience there to take Wigan forward, which could include making use of loan signings.
He said: "We're not always talking about buying players but for me the loan market has gone very well at Brentford Football Club.
"I have not seen enough of the squad to make any sort of adjustment now.
"I've worked in a different league and I'm catching up now but I see them every day in training and we have games in the Europa League and in the league.
"I'm sure that there will be one or two coming in, that does not mean for a lot of money - it is not necessary.
"To be honest we have not discussed it at all but it is natural that, when a new manager comes into a new club, there are maybe one two players he would want to bring in.
"Now is not the time to focus on new players, now is the time to get the best out of what we have because we have good players and that is my main objective."