The boss of the Swiss-German squad BMW-Sauber echoed the sentiment of the majority of F1's travelling circus, which argues that such a long break would be better suited for a point later in the season, when it makes more sense to have a rest.
The gap in the calendar emerged after Imola lost its provisional spot.
"Four weeks is too long," Theissen said. "Three would have been better."
BMW will, however, use the time "effectively", 55-year-old Theissen promised, both at the Hinwil factory and then at the upcoming Barcelona test.
He also advised team rookie Robert Kubica to relax and settle into his first full season of formula one this year, despite not looking as impressive as teammate Nick Heidfeld so far in 2007.
"Robert has enormous potential," Theissen insisted. "We know that the season will be a learning year for him.
"I have told Robert to take it easy. We are fully aware of his skills," he continued. "He just needs some problem-free races, then things will get going automatically."