Spanish rider Alex Rins, who injured his right leg at the Italian Grand Prix in early June, will miss the British race on 6 August.
The LCR Honda team announced on Tuesday that he is to be replaced on the grid by his compatriot Iker Lecuona.
After missing the German and Dutch races following his injury, 27-year-old Rins has not recovered in time for the race at Silverstone.
HRC rider Iker Lecuona, 23, previously replaced fellow Spanish rider Joan Mir in the Honda factory team colours for the Dutch GP on 25 June.
As MotoGP returns from its summer break, the current Italian world champion, Francesco Bagnaia, sits 35 points ahead of Spaniard Jorge Martin in second place.
Rins is 13th in the standings.