Pirelli has tweaked its softest tyres ahead of the last European pre-season test this week.
The move follows reports that the super-soft tyre has been ruled out for at least the opening four races of 2011, after it degraded severely after only one lap at Jerez.
"This compound will hardly be seen at a grand prix in 2011," Sebastian Vettel is quoted as predicting in Blick newspaper.
It is believed that is why Pirelli agreed to make some last minute changes for the Barcelona test, which is the last track outing before F1 moves to Bahrain.
"Pirelli will bring a modified version of the super-soft and soft tyres (to Barcelona), in response to feedback from the teams following the first official tests," the Italian supplier confirmed.