Fleming was appointed England’s new Test coach in July, yet he missed the 3-0 series win against Pakistan.
The former New Zealand captain will now arrive for meetings with the England hierarchy.
He is expected to watch some of England’s white-ball series against Sri Lanka, with the ODI and T20 teams still led by Fleming’s fellow Kiwi and good friend Brendon McCullum. Fleming could also visit some of the counties.
When McCullum was in charge of both the Test and white-ball teams, he kept the same backroom team across formats, including Trescothick as an assistant.
However, it now looks likely that the staff will be reorganised. Former Australia batter Mike Hussey said he was approached by Fleming, though it has been reported down under that Hussey has declined.
Trescothick said he has not got clarity on his future role. He confirmed he has a preference but declined to reveal it.
“It’s probably best I don’t mention it at the moment because it may not be the case of what happens,” he said. “I love doing both formats. It’s brilliant and I’ve been privileged to be in the position of assistant coach.”
Trescothick will be joined on England’s staff by former team-mate Kevin Pietersen, who has been appointed as a consultant for the white-ball team.
Pietersen, one of the most flamboyant and innovative batters to play for England, returns to the national team 12 years after he was effectively sacked following the 5-0 Ashes defeat in 2013-14.
The 46-year-old’s first day back in the England set-up is on Sunday, joining preparations for the first T20 against Sri Lanka in Southampton on Tuesday.
“We’ve spoken already, to plan a little bit,” said Trescothick. “I gave him a couple of things that I wanted him to look at, to get his advice on.
“He is buzzing. Putting back on the shirt or the tracksuit, he is buzzing for that opportunity.
“Having his presence around and the knowledge he has about batting – he sees batting in a different light to many different people. If we can tap into that, it’s only going to benefit the team.”