PETRUS du Plessis, the Glasgow Warriors prop they signed at Christmas to help solve a short-term injury crisis, is to stay with the club sharing limited playing duties with a new full-time role as a specialist scrum coach.

He have actually been working with the Glasgow pack since he arrived. There have been obvious improvements since he started feeding his input into the set piece, so it made sense for the club to try to keep him on board.

At first du Plessis, who featured in two Heineken Champions Cup-winning sides when he was with Saracens, will combine coaching with playing but at 38 his on-field role is likely to be limited and once players are back from the World Cup he will be there strictly as emergency cover and able to concentrate entirely on coaching.

His appointment is the final piece in the coaching jigsaw for Glasgow ahead of next season, and shows the way the club emphasis is evolving. By moving into the fourth assistant coach position he is, in effect, taking the spot previously held by Mike Blair, who is heading to a full-time role with Scotland.

Blair's role was all about skills and handling, a lot of it focussed on the backs – most of that will now be handled by Dave Rennie, the head coach – but du Plessis will unashamedly take on the job of trying to convert the Glasgow pack into the kind of monster unit that can batter and bully sides into submission.

Under Rennie, there has been an acknowledgement that the pendulum has swung too far in favour of fast, open exciting rugby at the expense of the basics and getting the front-foot ball that makes all that possible.

If they needed a reminder, confirmation of du Plessis's appointment comes just couple of weeks after the Guinness PRO14 final where they were taught a lesson in substance over style by Leinster, who adapted to the wet conditions much better and claimed the trophy as a result.

Du Plessis himself has clearly loved his short time in Glasgow and it cannot have taken much persuasion before he accepted the role, joining John Dalziel in a new coaching group in charge of the forwards

"I’m honoured to be given the opportunity to formally move into a coaching role with Glasgow Warriors," du Plessis said. “I’ve enjoyed my time at the club. I’ve been helping to coach the forwards over the last few months, so it’s great that I can now focus more on coaching, although I’ll still be available to play during the Rugby World Cup.

“I’ve enjoyed getting to know John Dalziel and I’m looking forward to helping him and the other coaches as we prepare for the new campaign.”

The coaching confirmation also ends any speculation about the future of Jason O'Halloran, the backs coach, who is there for at least another year while Kenny Murray will also stay on and take charge of defence.

There was also a contract confirmation across the country in Edinburgh with Damien Hoyland, the 25-year-old four-cap wing, signing a one-year extension to his current deal.

A series of injuries affecting his foot and knee have meant he has hardly featured since Richard Cockerill took over as head coach there, though did make the team for the Heineken Champions Cup quarter final against Munster.

"He’s an international winger who has shown he can perform at the highest level. It will be hugely beneficial for him get a full pre-season under his belt and he will be an important player for us at a key position,” was Cockerill's verdict.