The team are without a race victory in over a year and drivers Lewis Hamilton and George Russell are eager to fight from the front again.
This winter provides a chance for the Silver Arrows to make progress before the 2024 season, and Schumacher believes that pressure may be mounting in Brackley.
“It's very, very important for Formula 1 to have a strong Mercedes at the top again,” Schumacher told Deutsche Pressse-Agentur.
“Mercedes must turn the tide as soon as possible, there is no doubt about that. If that doesn't happen, the weak period will only last longer.
“If this continues, it would mean that they clearly no longer understand how to build a winning car. That would be fatal for a brand like Mercedes, given the successes of recent years.
“Red Bull probably has something surprising in store for the upcoming season that will surprise some people. There is nothing to suggest that Max Verstappen and Red Bull will not continue their dominance.”
With just 21 days left before testing, there isn’t a lot of time before the paddock discovers just where Mercedes are going to be directing their efforts in 2024.
A poor start could see them turn their attention to 2025 even earlier than usual, which is going to be the last season under the current technical regulations.