Pattinson did take two wickets but his selection ahead of Stephen Harmison and Matthew Hoggard caused a storm of protest and he now seems destined to be a 'one-cap wonder', having not played for England since.
England lost that match by 10 wickets on their way to a series defeat that led to Michael Vaughan's resignation as captain.
The uncapped Trott, who played Under 19-cricket for South Africa and a distant relative of Albert Trott, the 19th century cricketer who appeared for both England and Australia, has been drafted in as a potential sixth batsman should Andrew Flintoff's right knee injury rule the all-rounder out.
England, 1-0 up in the five-match series, did not have a spare batsman for the drawn third Test at Trott's Edgbaston home ground where his Warwickshire colleague Ian Bell was chosen after Kevin Pietersen, also born in South Africa, was ruled out of the remainder of the Ashes with an Achilles injury.
But Flower, himself a former Zimbabwe batsman and wicket-keeper, said he had no qualms about picking Trott, qualified for England through his father.
"That does not concern me," Flower said on Tuesday when asked about the 28-year-old Trott's South African links.
"He has already played one or two Twenty20 games for England, he has been on Lions (A) tours, he has been in that Warwickshire dressing room for a long time and it does not worry me."
And he was equally firm in stating that England's bid to regain the Ashes after their 5-0 drubbing in Australia in 2006/07 did not risk being derailed by the hype surrounding Flintoff's injury in what the fans' favourite has said will be his final Test series.
"We all realise the situation, we know he is struggling and we have our contingency plans ready and the people involved in those plans know where they stand," Flower said.
"If Fred (Flintoff) can't play, Trott is an option to bat at No 6 then we balance the bowling attack thereafter. We trust our top six to score the bulk of the runs and the others have the onus of taking the 20 wickets."
Trott was picked by England at Twenty20 level two years ago but in two matches against the West Indies two years ago he managed just 11 runs in total.
However, this season he has averaged over 90 in first-class cricket and Trott said he was grateful for the advice of Warwickshire coach and England selector Ashley Giles, the former Test spinner.
"You wait all your life to be given this sort of opportunity.
"It will be something new and Ashley told me on the phone earlier today (Tuesday) that every player is nervous before their first Test - I will look to enjoy the moment, be positive and believe in myself."
Source: AFP Global Edition