May 22 (GMM) Amid speculation about the struggling Nick Heidfeld's future at BMW-Sauber, team boss Mario Theissen vowed to keep the internal pressure off the 31-year-old German driver.

In the Monte Carlo paddock, BMW motor sport director Theissen insisted that Heidfeld is working hard to bridge the deficit to his teammate Robert Kubica, who similarly struggled one year ago.

"Last year we put no pressure on Robert and it is the same now for Nick -- pressure would not help," he is quoted as saying by the newspaper Financial Times Deutschland.

Theissen explained that BMW engineers are also taking responsibility for helping Heidfeld to get more comfortable with the F1.08, which the driver has described as more difficult to pilot than its predecessor.

Heidfeld acknowledged: "Formula one is my life so this is not a situation that I am enjoying."