LONDON (Reuters) - French driver Romain Grosjean will have a five-place penalty on the starting grid at next week's German Formula One Grand Prix due to an unscheduled gearbox change, his Lotus team said on Friday.

Grosjean finished sixth in Britain last weekend after suffering gearbox troubles in the closing laps.

"We are very fortunate that Romain didn't have the problem earlier in the race," said the team's technical director James Allison in a team preview for the race at Hockenheim.

"Unfortunately for Romain it means he'll take a five-place grid penalty at Hockenheim, but he certainly showed at Silverstone that dropping down the order won't stop him challenging at the sharp end."

Grosjean had to stop on the second lap at Silverstone to change his damaged front wing after a collision and charged through the field from last to sixth.

(Reporting by Alan Baldwin, editing by Clare Fallon)