Rankin, newly-qualified for England after five years of international cricket with his native Ireland, was the pick of the home attack against Australia in the sole NatWest Series match so far permitted by the weather.
Former dual Ashes-winning captain Strauss saw plenty there, and even beforehand when Rankin bowled against England on their 2012 tour of the United Arab Emirates, to conclude the 6ft 8in seamer must enter Ashes calculations.
As England headed south from rainy Birmingham for the fourth one-day international, still 1-0 down with two to play, Strauss made it clear he rates Rankin highly.
"He was very impressive," he said.
"I remember when we played against him in a warm-up game in Dubai, and we were all quite impressed by the pace and bounce he generated out there.
"He looks like he's matured a lot as a bowler. He knows what he's doing, and he's an excellent candidate to make use of the conditions in Australia."
Rankin will have to leapfrog other contenders if he is to be named in the full Test squad, expected to be announced in under two weeks' time.
But Strauss is confident that, given the chance, the 29-year-old has all the attributes required to make a success of Test cricket.
"I think he's very much part of England's plans. Otherwise, he wouldn't be playing in the one-day series at the moment," he said.
"There's no reason why he can't go on and become a really high-quality, fantastic Test match bowler.
"It's hard to get in that England side at the moment. With (James) Anderson and (Stuart) Broad in particular, there's only kind of one bowling slot that's up for grabs occasionally - and even that slot has been very well-filled by both Steven Finn and Tim Bresnan.
"It's hard to force your way in. But with bowlers, you always get injuries - and opportunities do arise."
England bowling coach David Saker knows from experience the value brought to any team touring Australia by height in their pace attack.
"England have quite a few tall bowlers, with Finn and Broad as well," Strauss added.
"So the question they'll be asking themselves is 'how many do we need?'
"They always obviously have the option of having someone like Rankin on stand-by with the performance squad.
"But he's going to be in their thoughts. I'm sure there will be long conversations about whether he can make a decisive difference in Australia."
There may be a few conversations too about another fast bowler - Australia's back-to-form left-armer Mitchell Johnson, after he bounced out Jonathan Trott in Manchester and then Kevin Pietersen before the rain arrived at Edgbaston.
Inconsistent Johnson goes to extremes, unplayable one day and unwatchable the next.
Strauss said: "He's a very dangerous bowler.
"We've seen him at his best; in Perth in 2010 he was phenomenal.
"The England players have seen a lot of him, and kind of know how to deal with him. But if it's his day, and he's on song, he's a handful for anyone."
He certainly was for Trott, twice over, producing a brute of a ball to have him caught-behind for a duck at Emirates Old Trafford and then giving the number three a torrid time in Birmingham too.
Australia will have banked those memories, and will doubtless revisit those plans to dismiss two of England's most prolific batsmen.
"People do remember," said Strauss.
"But if in the next innings, Pietersen starts smacking him over square-leg, then they'll forget about them pretty quickly.
"If you get out the same way two or three times in a row, then it's a problem for you ... you don't worry about it too much as a batsman, unless it's a recurring theme."
Trott's comparative struggles this summer - he averaged under 30 in the Ashes, compared with a career figure approaching 50 - have not gone unnoticed.
But Strauss expects him to battle back.
"I suppose it looks like Trotty's fighting with himself a bit at the moment," he said.
"He's had a tough summer, by his very high standards.
"But I've seen a lot of Jonathan Trott, as an individual and as a batsman, and he'll come back strong.
"One thing he does know how to do is keep calm out there in the middle and trust his gameplan - and that's always the best way to score runs consistently."
:: Andrew Strauss joined Michael Vaughan on his 500 mile charity bike ride, 'PruProtect Chance to Ride', in aid of Chance to Shine and Laureus Sport for Good Foundation. Sponsor Michael at www.chancetoride.co.uk.