The former Renault driver is set to be confirmed as Pirelli’s new tyre tester as the supplier seeks to remain impartial ahead of its return to Formula 1 in 2011.
Heidfeld left his Mercedes GP reserve driver role to take the test position with Pirelli just last month, completing three runs for the Milan-based supplier in Mugello, Paul Ricard, and Jerez.
However, Sauber lost patience with former McLaren test driver Pedro de la Rosa following a disappointing return to F1 racing for the Spaniard and announced on Tuesday that Heidfeld will rejoin the team for his third spell.
Grosjean, who competed in seven races for Renault in 2007, will test for Pirelli at Monza next week, and is understood to have already had a seat fitting in the Toyota TF109 set to be used.
Several driversÃ¢â‚¬â€including de la RosaÃ¢â‚¬â€have been linked with the Pirelli test role but the firm have yet to confirm if Grosjean will stay with them beyond Monza.
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