Kip Maxwell - who was replaced earlier in the season by ex-BMW Zyla driver Felix Beyer for an unknown reason - was still unavailable while Beyer himself was unwell and deemed unfit to drive by the medical team.
With Downton F1 desperate for a second driver to race alongside Thunder they called Parsons who could only happily oblige.
Having participated in the race however he released a statement saying: 'I am delighted that Bradley came to me - and felt he could trust me - so soon after my accident however I think my qualifying and race performances show that I'm not ready to come back just yet.
About halfway through the race I started to tire and the final 30 laps or so were very physically demanding and just took so much out of me. It is for this reason - and that I don't feel I can be competitive enough - that I have decided to sit out the remainder of the season.
I sat down with Bradley this morning and told him how I felt and while he said he would be sad to not have me in the car he understood that this is the best thing I can do for my career. I would like to thank Downton for the wonderful opportunity they have given me this season and I look forward to the future and whatever it may bring.'
With this it looks like formal confirmation that Parson will not continue with the team for next season and is therefore looking for a seat elsewhere.
Downton are yet to announce who will drive alongside Thunder for the next race in Belgium although it could well end up being their fifth different driver.
Kip Maxwell is still away on paternity leave and is also undergoing driver training with regular visits to a sports physiologist while Beyer has flown back to his native Netherlands for hospital check-up's.
If neither are available however, who will take the second seat? Will Powers relationship with Franklin F1 break down to such an extent he makes his Downton switch early? Or will Downton have to promote yet another youth driver? Only time will tell.