Mercedes boss Toto Wolff has admitted that the team are currently assessing how to approach the rest of this season in terms of their power units, after Valtteri Bottas was forced to use another fresh engine in Russia when his newly-fitted unit from Monza developed issues.
Bottas took on his fourth power unit of the season in Italy but, after just one race, was forced to fit a fifth in Sochi. This turned out to be out of necessity rather than tactical, with the fourth unit developing an issue that requires checking to see whether it can remain in his pool for the season.
With just seven races remaining until an engine freeze is introduced to Formula 1, Wolff said it's critical for Mercedes to get on top of their reliability concerns and figure out the best path to take with their power units.
"That's why we have a few balls in the air," he told media, including RacingNews365.com.
"You need to have the right balance between making sure that you've really sorted out all the gremlins that you have in the power unit, not only for this year but also for next year's power unit.
"We are in a phase of assessment [about] how to continue the season in terms of power units."
With Lewis Hamilton holding a slender two-point lead over Red Bull's Max Verstappen in the Drivers' Championship, Wolff said caution is key as an engine issue during a race at this point in the season could result in an insurmountable swing towards their rivals.
"It's always reliability versus performance," he said. "It's always a fine line that you need to get right.
"A DNF obviously is a no-go for the championship, and nobody, neither us nor our competitors, can afford the zero point race weekend."
Lewis Hamilton claimed his 100th Grand Prix win to move into the championship lead, but it's Red Bull and Max Verstappen who will be happiest after the Russian Grand Prix.