An arresting feature of England's last autumn international campaign was Manu Tuilagi's 15-minute, match-turning rampage through the New Zealand midfield to ensure that what had been a disappointing campaign ended on the highest of notes in what remains the All Blacks' only defeat since August 2011.

Tuilagi, then 21, is a player who by the 2015 World Cup will be a centre of experience rather than potential but as the England head coach, Stuart Lancaster, prepares for the gathering of his squad in Leeds next week in advance of next month's Tests against Australia, Argentina and New Zealand, midfield will vex him more than any other area, and more than the captaincy.

Lancaster on Wednesday added Henry Trinder and Joel Tomkins to the elite squad as replacements for Tuilagi and Brad Barritt, who will be out of action until December because of an ankle injury. Trinder, 24, has missed Gloucester's last two matches because of a hamstring problem, and may sit it out this weekend when his team travel to Munster, so Northampton's Luther Burrell was added as injury cover.

The trio join Billy Twelvetrees and Kyle Eastmond as the centres in the squad, five players with a total of seven caps and four Test starts between them, although Owen Farrell, one of three fly-halves in the 34, is an option at inside-centre, a position he regularly filled at Saracens last season.

Twelvetrees and Burrell are 12s, Trinder and Tomkins 13s with Eastmond comfortable in both positions. At the squad announcement, Lancaster kept repeating the word form: Tomkins and Burrell have been part of consistent teams this season, Saracens and Northampton respectively, but Twelvetrees and Trinder have had to make something out of the little supplied to them by the Gloucester eight.

Mike Tindall, the former England centre who is now player-coach at Gloucester, had called last month for England to consider Trinder as one of the solutions to their midfield injury crisis, calling him the "form player of the year by quite a long way" at Kingsholm. That his elevation came as a surprise was as a result of his absence owing to injury problems from the Saxons squad who were named in the summer. He has only made the rare leap straight into the elite set-up after the consent of Premiership Rugby, who could have blocked the double jump under the terms of its elite player agreement with the Rugby Football Union.

"He had an outstanding Churchill Cup when I coached the Saxons a couple of years ago and he has started the season really well," Lancaster said. "We have had a good look at him and he is chosen on merit. I know Luther well from his time at Leeds and he has come on since the summer tour to Argentina. Joel has also stood out and it is tough on Jonathan Joseph, as I told him. The others have made a difference and centre is such a competitive position that players have to show the X-factor."

The stand-out centres have been Burrell and Tomkins but would Lancaster risk an uncapped midfield pairing on 2 November against Australia who, for all their deficiencies in the tight five, remain one of the more inventive teams behind? It appears to be a matter of who starts alongside Twelvetrees, who made a notable impact on his Test debut against Scotland last February.

"Trinder and Tomkins have impressed us this season," said the England backs coach, Andy Farrell. "Harry has shown maturity to go with his quick feet and hands and a strong kicking game. He has been sensational. Joel has now reached the point where rugby union is instinctive to him and all credit to Saracens for playing him regularly last season: we are seeing the fruits of that."

Nigel Davies, the head coach at Gloucester who enjoyed a long career as a centre for Llanelli and Wales, has described Trinder as the complete package in his position. "He's got a fantastic skill-set, second to none – and I've seen a lot of centres in my time," Davies said.

The player sought to downplay expectations about his hopes of playing in the autumn. "Getting back into the mix with England was what I set out to do at the start of the season," he said. "All I could do was play really well and hopefully be in contention. I got a few injuries last season that put me off track so it's good to be back in there. The three autumn Tests are all massive games and it would be an experience if I were to be selected for any of those."