Cape Town - Eoin Morgan reasoned that giving international exposure to youngsters who could represent England for the next decade is more of a priority than how they fare in the ongoing ODI series against the Proteas.
The tourists chose to rest established stars such as Ben Stokes, Jos Buttler, Mark Wood and Jofra Archer, who was injured anyway, where South Africa retained a 1-0 lead after Friday's abandonment at Durban.
Fellow World Cup winners Adil Rashid and Moeen Ali are part of the squad but have not featured at either Cape Town or Kingsmead as England look to expand their player pool in the 50-over format.
With two T20 World Cups in the next 18 months, it is the sprint format that is at the forefront of Morgan's mind - and the Irishman will resist calls to bring back either Moeen or Rashid in the final ODI at Johannesburg.
Victory on Sunday is a must for England if they are to avoid a first ODI bilateral series defeat in three years, but Morgan insists the pair will only feature if it is felt they need some match practice for the three T20s.
Morgan said: "If they do come back it won't be to play our strongest team, it might be to get them some cricket under their belt.
"We don't have a T20 warm-up game, our priority is T20 cricket and those two guys come into contention for our best XI.
"If they do play then that will be the reason behind it, not because we want to level the series.
"I think we would have played them today if we were trying to kick on.
"There's a couple of things about this tour where we're looking to know more about people and present opportunity.
"Yes we want to win but we also want to know a lot more about other guys come the end of the tour with a longer-term plan in place.
"I think it gives them a platform for them to stake their claim for T20 and 50-over cricket because we've identified them as being the future and future potential England cricketers for the next 10 years.
"It's not about immediate results, it's about investing time in those guys."
Only 11.2 overs were possible at Durban, where South Africa, having won by seven wickets at Newlands, reached 71 for two in two brief windows of play - where the match was first reduced to 45 overs per side then 26.
Ultimately, the rain had the final say but not before Joe Root had bowled South Africa captain Quinton De Kock for the second time in two matches.
Morgan said: "Joe's an under-rated bowler, we certainly know that. When he's classed as a part-timer sometimes, it doesn't do him justice but he certainly does a great job for us."
Morgan was speaking a day after England announced Archer would be sidelined for three months with a low grade stress fracture of his right elbow.
Archer was a star performer in the World Cup and Ashes before enduring a more challenging first winter on England duty, and Morgan feels an enforced absence could be a blessing in disguise for the paceman.
Morgan said: "Jofra hasn't had a serious injury for some time now and I don't think this is a major issue.
"It allows him time - particularly when it's in his elbow - both to spend some time at home and get away from the game but also recondition exactly what he's built to do.
"We play a lot of cricket and stepping back from it sometimes, you reap the rewards and the benefits later down the line."