Romain Grosjean gets grid penalty for F1's Monaco Grand Prix

Grosjean finished eighth in the Spanish Grand Prix, but lost fourth gear for the final third of the grand prix.

On inspecting the gearbox, the team has decided to change the unit, with confirmation from the FIA expected later this weekend.

The penalty comes after Grosjean admitted he would be adversely affected by being the Lotus driver who will relinquish his car to reserve driver Jolyon Palmer for 10 free practice sessions over the course of this season.

"It does affect you quite a lot in terms of preparation for the weekend," said the Frenchman.

"FP1 is normally when you test new aero parts and you can do a back-to-back and you know that you do three runs of five or six timed laps and you assess what's the best part for the weekend.

"Then you get a first idea of the car and then you can do a set-up change for FP2, prepare your diff map, your brake map and then go into FP2.

"When you only start in FP2 you've got five timed laps on prime [tyre], three timed laps on option and then you go into your long runs so it's much harder to choose what is the right set-up.

"Then you can make some changes overnight but again, the Saturday morning is the not the same fuel load and under the same track conditions.

"It does affect you, I believe that's why not everyone is doing it.

"The more time you spend in the car the better it is, especially when you have very little testing in a year."