3) Rob Harley – Glasgow; 23 years; 6ft 6in; 16st 8lbsA series of impressive performances at both domestic and European level catapulted Rob Harley back into international reckoning during Scotland’s summer Quadrangular Tournament. His call-up midway through this summer’s series saw him play against Italy in the last-minute 30-29 win. As a former second-row, Harley is a handy line-out operator and ferocious competitor around the fringes, and further imposing displays for Glasgow throughout 2013/14 should see Harley push Kelly Brown, and maybe even John Barclay at blindside for a Scotland shirt.4) Craig Clarke – Connacht; 6ft 7in; 17st 9lbsPerennnially the weakest of the four Irish regions, Connacht head coach Pat Lam has significantly bolstered his playing resources with the arrival of former Waikato Chief and Super Rugby winner, Craig Clarke. Clarke has arrived in Galway with a big reputation, and despite his move to the Pro12 dashing his international, the 2012 ‘Super Rugby Player of the Year’ nominee brings a wealth of experience, leadership and consistency through his captaincy of the Chiefs. Clarke will undoubtedly have the respect of his peers to drive Connacht to improve on last year’s eighth-placed finish.Hungry for silverware: Gopperth’s mentality suits Leinster5) Jimmy Gopperth – Leinster; 5ft 10in; 13st 9 lbs LATEST RUGBY WORLD MAGAZINE SUBSCRIPTION DEALS From All Black to black and white: Former New Zealand scrum-half Brendan Leonard has singed for Italy’s ZebreBy James TennantThe thirteenth instalment of the RaboDirect Pro12 season is about to get underway as provinces, clubs and regions from the Celtic nations and Italy battle it out to reach the Grand final on May 31. As teams gear up towards the start of the new campaign, here are five players who can make a big impact for their sides over the coming months.1) Brendan Leonard – Zebre; 28; 6ft; 14st 6lbsOnce lauded by Graham Henry as the ‘best attacking scrum-half in the Super 14’, the 13-cap All Black scrum-half arrives in Italy off the back of two Super Rugby titles with the Waikato Chiefs, and every ounce of Leonard’s experience and tactical nous will be required if Zebre are to pull themselves off the bottom of the Pro12 table. Winless in their debut season, for Italian international rugby to grow it is important that both Zebre and Treviso continue to evolve and the wily Leonard, who has signed a two-year contract with the club, will be a key part of that.2) John Barclay – Scarlets; 26; 6ft 3in; 16 stStanding out: Flame-haired Rob Harley is always in the mixAfter a nine-year spell at the Glasgow Warriors, Scotland back-row forward John Barclay has sought new pastures by heading West to the Scarlets on a three-year deal. The issues Welsh rugby has had with player retention is well-documented, but Barclay’s arrival should soften the blow of George North.Beset with injury problems last season meant he fell down the Scotland pecking order, losing his starting berth as a result. A classic openside scavenger at the breakdown, who is also a prodigious tackler, Barclay will hope his Scarlets switch can resurrect his international career. NEWCASTLE UPON TYNE, ENGLAND – MAY 29: Jimmy Gopperth of Newcastle Falcons lifts the Championship trophy after victory over Bedford Blues in the RFU Championship play off final second leg match between Newcastle Falcons and Bedford Blues at Kingston Park on May 29, 2013 in Newcastle upon Tyne, England. (Photo by Alex Livesey/Getty Images) The departure of British and Irish Lion Jonny Sexton to Racing Metro was a major blow for Leinster, but head coach Matt O’Connor acted quickly to replace the seemingly irreplaceable by drafting in Junior All Black Jimmy Gopperth from Newcastle Falcons.A reliable goalkicker, his accurate boot sealed Newcastle Falcons’ Aviva Premiership return with 13 penalties in the two-legged RFU Championship play-off final. Gopperth’s unwavering ability to keep the scoreboard ticking over should prove invaluable as the Irish region look to reclaim their Heineken Cup crown. In competition with the rapidly improving Ian Madigan, Gopperth is a consistant performer in the fly-half jersey.