T20 star Malan faces 'tough' fight to break into England ODI side
The 33-year-old has climbed to the top of the International Cricket Council's T20 batting rankings, above Pakistan skipper Babar Azam and Australia captain Aaron Finch.
Malan now has eight scores of fifty or more in just 16 career T20 internationals, with an average of 48.71 and an equally impressive strike rate of more than 146 as he seeks to secure his spot in the side ahead of next year's T20 World Cup in India.
Jason Roy has recovered from a side strain and white-ball captain Eoin Morgan has been passed fit after a dislocated finger ruled him out of a five-wicket defeat by Australia in the third T20.
"He (Malan) is in great form, but the 50-over format is a tough team to get into," Silverwood said on Wednesday.
"If the opportunity comes around I'm sure he'll grab it with both hands, but it may be a case of waiting for that opportunity because it is such a tough team to get into."
By contrast, Adil Rashid looks set for a key role in the one-dayers, with Friday's match the first meeting in the format between the old foes since England's World Cup semi-final win over Australia last year.
The leg-spinner almost bowled the hosts to an unlikely win on Tuesday, with a return of 3-21 that included his dismissal of opener Finch with a superb googly.
Rashid's limited-overs form has revived the debate about whether he should return to Test cricket.
England's next two scheduled Test series are in Sri Lanka and India, where pitches traditionally favour spinners.
But Rashid's situation is complicated by the fact he does not currently play red-ball cricket for Yorkshire and has been managing a long-term shoulder injury.
England want Rashid to play some long-format cricket before he makes a 20th Test appearance, with Silverwood suggesting a warm-weather training camp may be a solution.
"There's a possibility of a red-ball camp with some competitive games on, so let's see," said Silverwood. "My thoughts on (Rashid's) situation remain the same. I'd like to see him with a red ball in his hand before we select him."
The Australia one-dayers will see England conclude a remarkable home season.
England's fixture list of 18 scheduled matches is set to be completed despite a campaign compressed by the coronavirus pandemic.
Silverwood praised the way his players had adapted to life in a bio-secure bubble and said motivation was never an issue when England faced their arch-rivals.
"It's Australia, they're all up for it," he said. "The one thing everybody feels in the dressing room is any win over Australia is great."