Steven Finn's Middlesex mentor Angus Fraser says the 21-year-old seamer is "not the finished article" and does not believe he will play in all five Ashes Tests.
Finn made his England debut in Bangladesh earlier this year and shot to prominence with some eye-catching displays against the Tigers and Pakistan in the summer.
But former England seamer Fraser, now director of cricket at Lord's, has warned against placing too much expectation on his charge.
"I'm naturally a huge fan of his but he is not the finished product and there is still some work to be done on him - he knows that," said Fraser.
"He knows that this summer was possibly a bit flattering in the way that he bowled alright but maybe the opposition and the nature of the pitches made life a little easier.
"He's got a lot to improve on from what he did this summer to be successful Down Under."
Fraser played eight Tests in Australia, with 29 wickets at an average of 32, and took six for 82 in just his second appearance Down Under in 1990.
He has passed some of his experience along to Finn but maintains it will be a tough time for him both tactically and physically.
"I've spoken to Steve a little bit about bowling in Australia and we've worked in the nets a bit as well," Fraser told http://www.lords.org.
"The principles of fast bowling are the same wherever you go. You can complicate it and dress it up as much as you want but if you hit a good length hard out in Australia then you've got a chance.
"It is different with the Kookaburra ball which doesn't offer the bowlers much help so he'll find it a bit harder in that respect.
"I'd be surprised if he played all five Tests because there are back to back Tests twice and there isn't a great deal of time at any stage to have a break.
"I'd like to think he has a very good chance of playing up front though - and going into the series he's in the side."
Should Finn, or any of England's other seamers, find the going too tough at any point in the series then the recalled Chris Tremlett is waiting for his chance to impress.
The Surrey paceman was named in the touring party ahead of Ajmal Shahzad after a three-year absence and Fraser thinks he has plenty to offer if required.
"If he can show the characteristics of desire and determination and combine those traits with what he's already got, then he can be a real surprise package," he added.
"He could come through quite quickly and put the other bowlers under a bit of pressure.
"If he gets it right and he's in the right place physically and mentally then he can be a real proposition because he's a tasty bowler."