Stuart Lancaster is prioritising versatility when he weighs up the final contenders for the 31-man Rugby World Cup squad but Sam Burgess' England role will be uniquely in the centres.

Burgess will make his England debut at No.12 in Saturday's World Cup warm-up against France at Twickenham despite having played the bulk of his union career in the back-row. Lancaster has already praised Burgess' performance in training but such are the confines of a 31-man party, versatility is king.

Lancaster will use Saturday's Test at Twickenham as an opportunity to see who sinks and swims in the international environment but Burgess' acid test will be purely in the centres.

Sam Burgess © Getty Images

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When Lancaster was asked whether Burgess would ever feature at blindside, he answered: "No, not with us. I understand why Bath do it. But think about the mechanics of the lineout. Tom Wood's role in the lineout is absolutely critical.

"Actually our lineout, as a functioning unit this weekend, with Calum Clark in has more options than we've had at any other time. If you went with Billy Vunipola at 6 and Ben Morgan at 8, that's a big difference."

Burgess' rapid rise to the Test team has raised eyebrows especially when his Bath team-mate Kyle Eastmond, who plays at inside centre and was first-choice last term, was jettisoned on Friday. But England are seemingly favouring having a ball-carrying centre in their midfield alongside a ball-player with Burgess filling the former void left by the exiled Manu Tuilagi.

But despite the fast-track, there are no guarantees a good performance will rubber-stamp his spot in the final squad.

"To come in and learn a new code is a difficult thing to do and he has done it effectively at Bath," said Lancaster. "His contribution in the Premiership Final was good, his physicality in defence - I remember him smashing Billy Vunipola once, things like that.

"He has brought those points of difference and worked hard to learn the game. This is the next step, to see if he can make the step to becoming an international player. I'm open-minded. I do think the longer he plays the game and the more opportunities we give him in training and games, the better he'll become. He's not got a free pass into the team because we've got other guys like Billy Twelvetrees and Luther Burrell who have done well."

While Burgess' role will be limited to the centres, Danny Cipriani may get a trial at fullback on Saturday. The final England squad is likely to have two out-and-out fullbacks but an impressive showing from Cipriani may force a rethink which could potentially see him included as one of three fly-halves with the Sale man doubling up as another option at No.15.

"We obviously did it on the Barbarians game. He has played for Wasps in the past there, he has been running in training there because you look at the balance of the backline: you can't have 3 specialist fly-halves. George couldn't play any other position, Owen could play 12, Danny is a 10 who could play 15 and Goode is a 15 who can play 10. You have your 2 fly-halves as your number one and number two and it's definitely something we will consider and would like to happen. But I don't want to prejudge it. It only takes an injury to Owen Farrell and he's playing at 10 [on Saturday]."

While England are weighing up the various permutations of the final 31-man squad what is now nailed in stone is, barring injury, Chris Robshaw will be England's World Cup captain. While some other countries, such as South Africa, name a vice-captain, Lancaster is not tempted to follow suit.

"I probably wouldn't have a nominated one because things can change. I'm certainly confident in Tom's ability to captain the side but equally, I'd be equally confident in Ben Youngs' ability to captain the side, if you look at the experience he's had. We'll see how it plays out during the course of the tournament but it's good for Tom to do it this time, but Ben could do it, I'm sure.

"In an ideal world, Robbo [Robshaw] plays, but very few players play all seven games in a World Cup. When the All Blacks won it in 2011, there were three players out of a 30-man squad who played in all seven games. They had Kieran Read captaining and various others."