Exeter Chiefs' preparations for their top flight debut have been hit by an injury to summer recruit Junior Poluleuligaga.

The Samoan scrum-half – one of Rob Baxter's key signings ahead of the new season – picked up a hamstring injury in last week's friendly defeat by the Scarlets. And it has proved serious enough to keep him out of tomorrow's big Aviva Premiership game against Gloucester at Sandy Park (3pm).

But scrum-half rival Haydn Thomas hopes to soften the blow for his team by taking his opportunity against his former club to cement his place in the side.

"It's great to start, that's what I want to be doing all the time," said Thomas, who played in the Premiership for Gloucester and Bristol before returning to Exeter last summer.

"I'm very happy and aiming to put a performance in so that I can keep my place and hopefully contribute to a winning team performance.

"There's always going to be competition, that's what it's all about. There's no point being involved in a club where there's no competition, it's not healthy.

"It's good for me personally to have that competition, it makes me try harder and harder and it's good for the club to have different options as well."

Thomas is one of three personnel changes to the side that lost 24-20 in Llanelli last Friday.

Phil Dollman comes into a re-jigged backline that sees Mark Foster switch to the wing and Bryan Rennie move in one place to inside centre. Matt Jess misses out.

The only change to the pack sees Tom Johnson start on the flank, with Chad Slade dropping to the bench.

Baxter said Dollman and Johnson had been rewarded with starts after impressing from the bench last week.

"Polu's injured. He's got a hamstring injury but we don't know how long he will be out for yet," said Baxter.

"Johnson came on and played very well against the Scarlets and I think that's a form selection. Chad will still have a good impact off the bench — he's been an important player for us all the time he's been at the club and he still will be.

"I think it's similar in the backs. Jessy will feel a little bit unlucky but he is a guy who'll have a big part to play for us this season. I think he's just not started in the form other guys have."

The Chiefs are expecting a bumper crowd for tomorrow's clash as there has been a big build-up to the club's maiden Premiership campaign.

But Thomas feels the players have to ignore the significance of the match and make sure they do what is required of them on the pitch.

"I think we need to concentrate on what we usually do and not change anything in terms of our preparation and how we approach these games," he said. "It's a big day for the club but I don't think we need to get wrapped up in that — we'll go out and do what we usually do and go and play rugby.

"We all play the game to win matches and that's what we're aiming for."

Tomorrow's match will only be the second time Thomas has faced Gloucester since he left for Bristol in 2007.

The Exeter University graduate scored three tries in 28 appearances for the Cherry & Whites and is looking forward to playing against old friends. It will be nice to play against Gloucester. They're a very well supported team, as we are, so I'm sure the atmosphere will be really good," he said.

"It will be great to play in it and hopefully we'll get a result. "There's a couple of my mates at the club still but there's been no real banter, I try to detach myself from that."