Rob Harley believes international rugby is making a marked improvement in his game - even when he is left out.

The Glasgow back-row forward is in Vern Cotter's squad for the autumn Test programme against Australia, Argentina and Georgia but he has not always been a regular under the New Zealander.

Having been an ever-present in Scotland's 2015 RBS 6 Nations campaign, Harley missed out on the World Cup later that year. It was a full year until he returned to the team, against Ireland in the final Six Nations game, although a thumb injury had ruled him out of the opening matches.Glasgow Times:

But Harley has always been given specific feedback about why he was omitted and what he needed to do to get back in, and the competition for places has helped push the 26-year-old on.

When asked to assess his recent Scotland career, he said: "It has probably not been ideal for me personally but I have been on the cusp of squads and been in and around the team at Six Nations time.

"The last Six Nations game I was involved and the World Cup warm-ups, although I didn't make the team there.

"I think it's just testament to the competition we have, it just shows wherever you are playing you have to be driving your game forward.

"You look around and see the guys in the position around you, they are good players and we are constantly improving. I think that benefits me as a player, to have that pushing my standards."

Harley, who has won 18 caps since his 2012 debut, feels he turns the pain of rejection into a positive force.

"You are constantly trying to improve yourself," he said. "It does put it into focus that there are things you can do and things you can work on. It gives me better clarity, I have definite things I can work on.

"We get good feedback on what the coaches want to see from us and where we can improve our games.

"As well as that, at Glasgow we are getting feedback on how we are playing and where they see both improving our strengths and our weaknesses in our game and just trying to be better rugby players.

"But part of the good thing about being in the Scotland camp is you pick up skills from other guys, the techniques and skills they are using. You learn a lot being in the camp."

Harley also credits Cotter, who is in his final season as Scotland head coach, with making him a more rounded rugby player.

"He came in with a very open mindset as to what forwards should do," Harley said.

"He wasn't limiting us to only being ball-carriers or only something else. He was saying you are assessing the options in front, if it's the right option you can tip the ball on, you can be ball players.

"It's about making sure you are complete rugby players but also having that core emphasis on physicality because it's a physical game, and just having that focus that the team that goes forward all the time is going to get good results."