Mercedes says the next two races will be key to deciding whether or not it will choose to take one or more deliberate engine penalties for Lewis Hamilton this season.

The reigning world champion had taken the greater share of Mercedes' reliability dramas this season, with a spate of failures earlier on in the campaign.

In particular, a run of back-to-back MGU-H breakdowns at the Chinese and Russian Grands Prix means he has already used his full allocation of that power unit component up until now.

He has also used all five turbos so far too.

Hamilton is well aware that his world championship hopes are made more difficult by the prospect of penalties, which could leave him with grid penalties and an uphill battle against Nico Rosberg.

If Mercedes feels that it cannot avoid Hamilton getting a penalty, then it will want to make use of an engine change at a track where overtaking is easier, so the grid penalties will not be so costly.

The most logical place is Spa-Francorchamps, where the long straights would allow Hamilton to recover better than at other venues like Singapore or Suzuka.

Mercedes boss Toto Wolff says a decision on what it plans to do will be made over the summer break, and will rest on how good Hamilton's reliability is at the Hungarian and German Grands Prix.

When asked if the team had made its mind up yet about Hamilton's penalty prospects, Wolff said: "We haven't yet. We were trying to make it on four and it is clear we are making it on five.

"It looks like that we might have a penalty with him, but we don't know. We need to see the next two races how that is going to pan out and decide after the shutdown or during the shutdown."


Gallery: Mercedes: Next two races will determine Hamilton engine penalties