The Leeds boss has been discussing the executive director's departure - but has added a sense of perspective.
Indeed, Pearson rejoined the Whites as owner Massimo Cellino's executive director this summer but left on Tuesday night after just four months in the job.
Rosler insists Leeds will stay strong and move on, though, but admits the 50-year-old will be a big miss for United.
Rosler told LUTV: "I worked very well with Adam and Massimo Cellino worked well with him. Unfortunately, Adam decided to go.
"We're all sad about that because he brought knowledge to this football club and also human qualities. But we all have to move one, it counts for the players and for the whole club."
Pearson's exit came on the night Leeds suffered their first Championship defeat of the season - a 1-0 loss to Ipswich Town - so fans, coaches and players alike will need to dig deep to recover some morale ahead of this weekend's trip to MK Dons.
Rosler's sensible reaction is the way to go, though, as United have only lost the once and a win in Milton Keynes will put a good spin on their season so far, just as victory at Derby County did.
Following Pearson's exit, meanwhile, the Yorkshire Evening Post have reported that Cellino will not be hiring a replacement and simply doubling his own workload.