Lawson faces fight to be fit for Tests after broken hand

• Rory Lawson's impressive displays last season landed him a key role in the summer Tests

With Mike Blair off form and Chris Cusiter injured, Lawson's performances for Gloucester in the second half of last season pushed him into the driving seat for the summer tour where he impressed coach Andy Robinson by working with Dan Parks to steer Scotland to a first Test series win in the southern hemisphere.

Cusiter returned early from the tour without being involved in the Tests, his knee injury having shown no sign of improvement, and despite a summer of rehabilitation he failed to make a full recovery. In August, further tests to get to the bottom of the problem revealed a fractured knee-cap and the scrum-half was forced to undergo surgery that is now expected to keep him out of the game at least until January.

Blair has started this season in good form despite Edinburgh's struggles, while Lawson recovered from a rib injury that kept him out of the opening game to start the past three games for Gloucester and captain the side in Sunday's win over Wasps, so a new battle for the pivotal position was looming. However, Lawson was replaced 15 minutes from the end of Sunday's thrilling Aviva Premiership win. He was unable to close his hand properly and tests have revealed a fracture. The scrum-half will have surgery on Thursday and have screws inserted to stabilise the injury. A four-week lay-off is the likely result.

That would take him up to the end of October and give him just two possible games, against Leicester and the Newport Gwent Dragons, in which to prove his fitness for a place in Scotland's squad to face New Zealand on 13 November.

Meanwhile, Wales centre Gavin Henson is set to make his return to rugby after accepting an invitation to play for the Barbarians against South Africa at Twickenham in December.

The Ospreys back has not played since March 2009 after suffering an ankle injury in an Anglo-Welsh Cup defeat against Gloucester and then opting to go on unpaid leave. The 28-year-old, who is appearing on the BBC's Strictly Come Dancing programme, has been linked with moves to several Aviva Premiership clubs including Wasps, London Irish, Harlequins and Bath, but all have denied discussing a move.

The player was also recently selected to model the new Wales kit in a marketing campaign, upsetting several members of the current national squad.Henson now appears ready to lace up a pair of boots again, having voiced his desire to play for his country at next year's World Cup in New Zealand, although the Barbarians will monitor his fitness ahead of the Twickenham clash.

Henson will be joined in the Baa-Baas squad by Ospreys team-mate Mike Phillips, while Australia's Rocky Elsom and Matt Giteau, who played in the invitational club's win over the world champion Springboks in 2007 and against New Zealand last autumn, will also appear. Former Saracens and New Zealand lock Chris Jack is another returning face for the traditional end-of-tour fixture. South Africa will face Tests against Ireland, Wales, Scotland and England as part of their Grand Slam tour, before finishing up against the Barbarians who, as was the case against New Zealand, will be coached by Nick Mallett and Alan Solomons.

Barbarians' president Micky Steele-Bodger said: "Both Nick and Alan made a big impression last December and we had no hesitation in inviting them back to work with our squad again."