Allen and Tuilagi have been arguably the strongest midfield combination in the top flight this season, but the Premiership Young Player of the Year is to miss the title decider after being handed a five-week ban for his three-punch attack on Northampton wing Chris Ashton during a fractious last-four clash 13 days ago.
Matt Smith has been handed the number 13 jersey in Tuilagi's absence, with Argentina international Horacio Agulla on the wing as Leicester prepare to face a direct Saracens centre combination of Brad Baritt and Chris Wyles
Allen, 24, admits losing his powerful midfield partner is a loss for the reigning champions, who are in a seventh-straight final, but is confident they have enough strength in depth to cope.
He said: "Manu has played very well for us this year and he is a great prospect for us for the future.
"We complement each other very well, he is a massive threat to defences which opens things up for me a bit. He has the natural ability and is very good at what he does.
"But we have a strong squad here and all the guys here are capable of doing the job when called upon."
Allen was part of the Tigers side who beat Saracens in last year's dramatic final, widely regarded as the best yet, and is prepared for another nail-biter at the home of English rugby.
Saracens have had the edge over the east Midlands giants - who will seal a hat-trick of Premiership titles with victory on Saturday - this season, claiming the spoils in the two league meetings this term.
And Allen said: "Sarries have showed that they are a good group and they will be again in the final.
"They also beat us at home last year before the final . We were slightly off that day, we were at the top of the table and we weren't quite right mentally.
"But come the final it's a different story as we have shown the last few years. Last year it came down to the end and hopefully we can pull out the goods again."
Allen's excellent form during his second season at Welford Road has led for calls for him to be recalled by England, having won two caps as a callow 20-year-old under Andy Robinson during the 2006 autumn internationals.
But he has yet to receive a call from Red Rose team manager Martin Johnson as the World Cup looms increasingly large on the horizon.
While Allen is frustrated not have seen his consistency rewarded, he is grateful to Leicester for helping to revitalise a career that seemed to have stalled during his final season at Gloucester.
"It is a bit frustrating," he said.
"But it's a personal choice of what the England management feel is best. All I can do is keep playing well. I have a final to go to, and it would be massive for me to get a second championship medal.
"I have to continue to play well on the bigger stage, and if we can do as well in the Heineken Cup next season who knows what can happen.
"But I can't do anything other than continue to work hard here with guys like (head coach) Matt (O'Connor) and the rest of the coaches.
"I have come on a lot in my two years here, more so this season as I have grown in confidence after bedding in to the team.
"I know what they want from me, and the hard work goes on in behind the scenes.
"The balance is right here, that mentality we have here. It's not as hard and brutal as it was here years ago but (rugby director) Richard Cockerill believes that people putting in the graft and hard work will benefit from it. They are getting it spot on."
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