The Durham fast bowler could be the first player to benefit from the changes, which allow teams to use a substitute for the first time as part of an International Cricket Council initiative to spice up the present one-day format.

The new rules, which include only 10 overs of fielding restrictions at the start of the innings followed by two further blocks of five over restrictions to be used at the fielding captain's discretion, are to be used in the three-match series for the first time before being trialled worldwide.

Harmison's role is expected to be affected most by the changes, particularly when he bowls during the middle part of the innings when the new fielding restrictions are expected to be implemented.

But he could also be the person withdrawn after bowling his overs to allow England to supplement their batting order by bringing on Matt Prior, brought into the squad for this series, or Vikram Solanki.

"I'm looking forward to putting my feet up," admitted Harmison. "This is a new thing the ICC want to have a look at and I'm sure if it's good they will keep it in and if it's not they'll quickly chuck it out.

"I've always said it's a batters game and these new fielding restrictions have proved that. I'm looking forward to it. If we can get somebody else into bat who averages 35 or 40 in one-day internationals then I'm sure people would prefer to watch him bat than watch me bat who averages four or five.

"It wouldn't bother me if I was the one taken off - I can bowl a few more bouncers and not get them back! The public want to see some exciting cricket and I'm sure the public would much rather see Matt Prior bat than Steve Harmison."

Both sides have been considering the use of the new rules, particularly the selection of their substitute, who must be named before the toss and can replace any player at any time during the match.

"You're not going get a full indication of these rule changes until they've been in for 10 or 15 matches," claimed Harmison.

"There are a lot of theories going around at the moment, but nobody really knows what's going on until it actually happens. It will be interesting to see when both captains decide when is the right time to take the five overs of fielding restrictions."

England are expected to retain the side that fought back heroically to tie Saturday's NatWest Series final against Australia at Lord's for today's opening match at Headingley, with Prior strongly tipped to become their first named substitute.

Teams for Thursday's NatWest Challenge match between England and Australia at Headingley:

England (from): MP Vaughan (captain), ME Trescothick, AJ Strauss, PD Collingwood, A Flintoff, KP Pietersen, GO Jones (wicket-keeper), AF Giles, CT Tremlett, D Gough, SJ Harmison, J Lewis, VS Solanki, CT Tremlett, MJ Prior.

Australia (from): RT Ponting (captain), ML Hayden, AC Gilchrist (wicket-keeper), DR Martyn, MJ Clarke, A Symonds, MEK Hussey, GB Hogg, SR Watson, MS Kasprowicz, B Lee, JN Gillespie, GD McGrath, SM Katich, BJ Haddin.

Umpires: RE Koertzen (South Africa) and MR Benson (England).

3rd Umpire: NJ Llong (England).

Match Referee: RS Mahanama (Sri Lanka).