Foreign imports Octavio Bartolucci and Daniel Parks will make their Premiership debuts when Leeds tackle Bristol at the Memorial Stadium on Sunday.

Tykes coach Phil Davies has wasted little time drafting in the pair following successive defeats against London Irish and Northampton.

Wing Bartolucci was recruited from French club Agen, having scored eight tries in 22 Tests for Argentina, while Australian fly-half Parks is also highly-rated and replaces injured playmaker Stephen Bachop.

Parks amassed more than 350 points during the recent Sydney club competition season, breaking a record previously held by former Australian international David Knox.

Leeds, who will embark on their European Shield campaign next week in a testing qualifying group which also includes Beziers and Pontypridd, face a difficult task against Bristol.

Home coach Dean Ryan has made three changes from the side held 19-19 by London Irish six days ago - calling up full-back Matt Carrington, fly-half Felipe Contepomi and flanker Matt Salter and leaving Davies under no illusions about what lies ahead.

"We will need to be on our game, both mentally and physically, to compete with Bristol," he said.

Irish should make home advantage count when Newcastle arrive at the Madejski Stadium, especially because they boast current Premiership top points-scorer Barry Everitt.

The diminutive fly-half is currently averaging 21 points a game, although his phenomenal standards slipped slightly last weekend as he let Bristol off the hook through three penalty misses.

"I get tired of saying this, but every game in the Premiership is a tough one," claimed Newcastle coach Rob Andrew. "You will lose if you are not sufficiently mentally and physically prepared.

"We are good enough to go there and win if we are on top of our game, and that has to be the case every week, because if you are not on top of your game, then you get beaten."

Newcastle, opening weekend conquerors of league champions Leicester but without a win since then, include both their England squad members Jonny Wilkinson and Dave Walder.

Saracens and Northampton, opponents at Vicarage Road on Sunday, have won their last two matches; yet Saints will be underdogs given that four players - Budge Pountney, John Leslie, Tom Smith and Mattie Stewart - are unavailable because of Lloyds TSB Six Nations Championship commitments.

Paul Grayson will captain much-changed Northampton against Saracens on Sunday, with his sights firmly set on a third successive Premiership victory.

The Saints have been shorn of numerous front-line players due to Six Nations Championship commitments and injuries.

Skipper Budge Pountney, centre John Leslie, together with props Tom Smith and Mattie Stewart, are all on Scotland duty against Ireland this weekend, while French lock Olivier Brouzet is out injured.

But former England fly-half Grayson has no concerns about leading Northampton into battle at Vicarage Road.

"Although we've had to make a lot of changes, everyone knows their job so well and I will just let the guys get on with it," he said.

"I am confident that this is an easy team to captain, because everyone knows what they are doing."

Saints recovered from a poor opening day display at Gloucester by recording emphatic wins against Bath and Leeds, so Saracens will not expect an easy time, even allowing for Northampton's absentees.

"Before the season started, if someone had offered us three wins from the first four league games, then we would have taken it without hesitation," Grayson added.

"If we get a victory at Saracens, then that would represent a good start to the league campaign."

England Under-21 captain Mark Tucker is set to replace Leslie, with Kelvin Todd deputising for Smith and Chris Budgen, a summer signing from Birmingham/Solihull, taking Stewart's jersey. Given Pountney's absence, Mark Soden or Andy Rennick can expect a back-row starting place.

Saracens rest scrum-half Kyran Bracken, who was given the all-clear by a neurosurgeon this week after taking blows to his head during successive league games, and promising young Welsh three-quarter Tom Shanklin.