Last year's winners made Crystal Palace the only Barclays Premier League casualties on Saturday as Latics extended their unbeaten run in the FA Cup to 10 games with a 2-1 victory.
Sky Bet Championship club Wigan have already played 36 times this season and another cup run could be seen as detrimental to their bid to return to the top flight, which remains the main priority at the DW Stadium.
However, their exploits at Wembley last May are still fresh in fans' minds and Rosler, who this week brought in Chelsea's Josh McEachran on loan, is confident they have a big enough squad to try to continue the club's love affair with the FA Cup.
"We have 21 games left in the league, plus we're still in the cup - which we're very happy with," he said. "There's a lot to play for and I think we needed to bring in bodies and quality to achieve our goals."
The ex-Brentford boss has been a strong advocate of squad rotation, which he has had to be with Wigan playing at least twice a week in all but two of the weeks since he was appointed on December 7.
That policy meant Republic of Ireland international James McClean missed out against Doncaster, who beat Rosler's side 3-0 last Saturday in the Championship.
But, restored to the starting line-up against Palace, the 24-year-old winger set up Ben Watson's opener before scoring the winner.
It was his first official goal for the club he signed for from Sunderland in the summer after a strike at Sheffield Wednesday in December ultimately did not count when the contest was abandoned.
Rosler added: "He wasn't in the squad against Doncaster and he responded very well.
"He had a very good game; he was a threat throughout the 90 minutes. He has a very good energy level and he can play at 90 minutes for a high-tempo.
"I'm happy for him, I think this goal will give him confidence. His general overall play will give him confidence. He played against a very good overall defender in (Adrian) Mariappa and I really like him. He caused him a lot of problems on that side."