The Indian driver will be replaced by Sakon Yamamoto in Hockenheim, the man who took SennaÃ¢â‚¬â„¢s seat for the British Grand Prix at Silverstone last week.
Initial rumours from the paddock suggested an e-mail critical of HRT team boss Colin Kolles from Senna was to blame for the BrazilianÃ¢â‚¬â„¢s omission, but a late statement at the race from Kolles revealed Senna would return, with many pundits saying he was back for the rest of the season.
But there was scepticism over whether he would be back for every race, with HRT also having Yamamoto and Red BullÃ¢â‚¬â„¢s Christian Klien on their books, and short of money to fulfil their obligations.
While most expect that Senna will compete in most of the races until the end of the season, there will be times when he, like Chandhok, will have to step aside as the other drivers can provide a welcome cash boost to the team through personal sponsors.
There is also a very real threat that one or both drivers could be dropped in favour of replacements who can bring more money to the team through sponsors.
Yamamoto is one driver who is financially well-backed, which would explain his inclusion at Silverstone and Hockenheim, while Mexican GP2 driver Sergio PÃƒÂ©rez, a target for Virgin Racing next season, and backed by billionaire Telmex owner Carlos Slim, could also be in line for a drive.
Hispania have been the slowest of the new teams so far this season as a lack of funding has prevented them from developing their car as much as fellow new boys Lotus or Virgin Racing.
The team were rumoured to have purchased parts from ToyotaÃ¢â‚¬â„¢s old chassis, but with a lack of available funds, it is not clear how much truth is in the story. Regularly bringing in well-backed drivers could go some way to remedying that.
Indeed, it has been suggested that YamamotoÃ¢â‚¬â„¢s inclusion over the two races would pay for significant parts to aid the development of the teamÃ¢â‚¬â„¢s 2011 car.
MORE: The latest football news
MORE: The latest tennis news
BIOGRAPHY: Cesc Fabregas