The number 58 has been retired by MotoGP ahead of the San Marino Grand Prix, in tribute to the late Marco Simoncelli.
Italian rider Simoncelli was tragically killed at the age of 24 when he fell from his bike at the 2011 Malaysian Grand Prix before being hit by two other riders.
His home circuit in Misano, which hosts round 13 of the 2016 season this weekend, was duly renamed Misano World Circuit Marco Simoncelli.
And Simoncelli's racing number has now been retired in further recognition of the former 250cc world champion.
It was also announced on Thursday that Misano will remain on the MotoGP calendar until at least 2020.
This weekend, Marc Marquez is aiming to extend his healthy championship lead over Valentino Rossi, which stands at 50 points despite the Spaniard finishing fourth at Silverstone last time out.
"Of course Silverstone was not the best final result, but we lost only three points and I've still got 50 points of advantage," said Marquez.
"Misano is a completely different track compared to Silverstone, everything is tighter and smaller. We have hard braking points and also three hard points of acceleration, but it looks like we can manage that better now, so we will see."