Six Nations 2016: Scotland's Mark Bennett 50-50 for Calcutta Cup

Bennett was a try-scorer during Scotland's World Cup campaign

Scotland centre Mark Bennett may return from a shoulder injury sooner than expected to face England in the Six Nations opener on 6 February.

He was hurt playing for Glasgow earlier this month and it was feared he would miss the tournament's early rounds.

Bennett, 22, was nominated as one of the breakthrough players at last year's World Cup.

"He is progressing well and we should know next week," said head coach Vern Cotter. "It is 50-50, I would say."

Alex Dunbar sustained a thigh strain in Glasgow's win over Racing 92 on Saturday, while Peter Horne is struggling with a foot problem and Richie Vernon is a long-term injury absentee.

That leaves Matt Scott and Duncan Taylor as the only currently fit centres in Cotter's squad.

Cotter admits Scotland's squad lacks depth

"Do Scotland have good strength in depth? No," said Cotter, whose side lost all five of last year's Six Nations Tests.

"We've got some good character and we've got some good individuals, but if we get banged up we know what that means.

"The players believe they can be competitive. A lot of things in this game are based on momentum so starting well will be important.

"We don't want to add stress and weight on the shoulders of the players. They want to win every game."

'No regrets and no excuses'

Scotland lost all of last season's Six Nations matches

Some Scotland head coaches have in the past been set a win ratio target for the tournament but Cotter insists he does not have one this year.

"It hasn't been mentioned," he explained. "I know they'd like us to win every game as well. The players want to perform well in the jersey.

"To use an old expression, we don't want to have any regrets at the end."

Since Scotland's 35-34 defeat by Australia in the quarter-final of the World Cup, a number of players have spoken about the pain of that loss following a controversial penalty decision by referee Craig Joubert.

And while Cotter has sympathy for the players, he wants them to move on.

"The memory of the World Cup will stay with the players for a long time but it's part of history now," added the New Zealander.

"I feel for them. I don't think I need to use it [as motivation] as the desire in the team is to improve. That's the energy generated within the team and the driving force within the group and that's a great mentality.

"There is a 'no excuse' mentality within the group. It's about what we can do."