Scotland have suffered a major blow after it was revealed that star centre and captain Sione Tuipulotu will miss the entire Guinness Six Nations because of a chest injury.

Tuipulotu is to undergo surgery on the pectoral muscle that was damaged in training for Glasgow Warriors last week and has been ruled out of action until later in the season.

The 27-year-old is clear favourite to claim the number 12 jersey for the British and Irish Lions in Australia this summer so his expected return towards the end of the campaign will come as a relief to the tourists’ head coach Andy Farrell.

Lock Scott Cummings could also be unavailable for the whole Six Nations after he fractured his arm in Glasgow’s 24-7 defeat by Harlequins on Saturday night.

A date for his comeback has not been set with Scotland yet to rule him out of the Championship, which opens against Italy at Murrayfield on February 1.

Cummings had forged a solid second-row partnership with Grant Gilchrist but head coach Gregor Townsend at least has Jonny Gray to call upon as an alternative following his return from knee and ankle problems.

With Tuipulotu unavailable, Rory Darge and Finn Russell will co-captain Scotland to reclaim the roles they performed in last year’s Six Nations.

In an indication of his growing influence on the team, Tuipulotu was placed in charge for the autumn and had retained the leadership duties for the Championship only to suffer his pectoral injury.

He has been one of the best-performing players in Europe and a standout centre in either hemisphere with his power as a carrier matched by subtler touches, making him a frontrunner for Lions Test selection.

“Sione Tuipulotu will miss the Six Nations after sustaining a pectoral muscle injury during a training session with Glasgow Warriors last week,” a Scottish Rugby statement said.

“Sione will undergo surgery this week and is expected to return to action before the end of the season.

“Scott Cummings sustained an arm fracture during Glasgow Warriors’ match against Harlequins at the weekend.

“He is also likely to miss the tournament and will undergo further review to determine when he will be fit to return. There will be no additions to the squad at this point.”