• Saracens take on Gloucester at Allianz Park on Saturday • Dylan Hartley’s fitness still a concern for Northampton

The Saracens director of rugby, Mark McCall, has warned of the threat posed by Danny Cipriani in Saturday’s Premiership semi-final, urging his side to cut the Gloucester fly-half off at the source.

Saracens head into Saturday’s encounter at Allianz Park hot favourites to reach the final as they hope for another European and domestic double, having reclaimed the Champions Cup earlier this month.

Cipriani meanwhile, has guided Gloucester into the play-offs for the first time since 2011 and his impact in his first season at Kingsholm was acknowledged last week when he was voted the Rugby Players’ Association’s player of the year.

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Twelve months ago, Cipriani was also part of the visiting team to Allianz Park at this stage of the season with Wasps but despite his best efforts Saracens ran out comfortable winners.

Playing behind a beefed-up pack with a distinctly South African feel, Gloucester are hopeful of laying a better platform for Cipriani to shine in his duel with the England captain Owen Farrell on Saturday, and McCall acknowledged Saracens must not allow that to happen.

“He’s a brilliant player,” said McCall, who confirmed Billy Vunipola and Jamie George would be fit to face Gloucester after they sustained shoulder injuries against Leinster. “Their starter plays, for example, are as good as anyone’s in Europe. They take some looking after and some planning. He does many things so well but we don’t necessarily focus on him. The focus is on trying to win a lot of other things which make his life more difficult.

“If he gets front-foot ball and he’s playing off momentum the whole time he’s very, very good. Obviously we want that not to be the case. We want him to have some difficult slow ball and that makes the decisions that much harder for him.”

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Saracens won the double in 2016 but the following year suffered a narrow semi-final defeat by Exeter in their Premiership semi-final the week after successfully defending their European crown.

After their well-documented celebrations following victory over Leinster in Newcastle, McCall described the extra week’s preparation to face Gloucester – who have fitness concerns over Ollie Thorley and Ed Slater – as a “godsend”. He added: “There is this hangover from 2017 and how that opportunity got wasted – we don’t want to let that happen again.”

McCall also brushed off comments from the Gloucester chief executive, Stephen Vaughan, who this week claimed Saracens should face a points deduction if they are found guilty of breaching the salary cap by Premiership Rugby. “There’s [an investigation] ongoing, isn’t there?” he said. “We should probably let that come to a conclusion.”

In Saturday’s other semi-final, Northampton return to Exeter for a repeat of last Saturday’s fixture but have insisted they are not prepared to gamble on the fitness of Dylan Hartley.

The 33-year-old has been sidelined since December with a knee problem and while Reece Marshall is a doubt because of a hamstring injury, Northampton will again make a late call on whether Hartley is ready to return.

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If he misses out and Northampton fail to reach the final he would face beginning England’s World Cup preparations next month without having played at all this year, though there is the possibility he could be included in next week’s squad to face the Barbarians.

The squad to face the invitational side will be largely compromised of players not involved in the wider World Cup training squad group but there is a degree of wiggle room.

Next week’s squad will also be overseen by Hartley’s former Northampton director of rugby, Jim Mallinder. “As the curve of his recovery has been pretty undulating, there is an element that we don’t want to put him back in when he’s not quite right. We’ll give him until the 11th hour,” said Northampton’s assistant coach, Phil Dowson.

“He’s pretty philosophical about it. He’s old now. He’s bright enough, knows his body well enough and he’s played enough rugby to know that if he pushes it now then he misses an obvious opportunity down the track. But at the same time he wants to be involved in the first semi-final for quite some time.