The Aston Villa boss opted to leave the Belgian centre-forward out of his squad for Saturday's trip to the Britannia Stadium, where they endured a 2-1 defeat to Stoke City.
Lambert's decision was influenced by a knee injury which Benteke picked up whilst on international duty in November.
It is a knock likely to keep Benteke out of Villa's Boxing Day date with Crystal Palace but Lambert insists his worries are less with the 23-year-old's fitness, more so his recent displays.
"It's not a major concern," Lambert told The Sun.
"But it's something that needs to have a little bit of a rest and to have treatment.
"The injury was contributing to his form but it was his general game that probably hasn't been what everyone hoped.
"It's not long term - at least I'm pretty sure it's not."
Despite stealing the headlines last term with a return of 19 Premier League goals, Benteke has failed to net in his last 10 outings.
However, Lambert remains assured a period of rest will enable the striker to regain his form of old and return much stronger.
"Hopefully this break will help him," he added. "Sometimes you play through knocks.
"But, at this level of football, you have to be bang on it.
"We have to get him back 100 per cent."