Scotland captain Sione Tuipulotu has been ruled out of the upcoming Six Nations through injury.

The Glasgow Warriors centre suffered a pectoral muscle injury while training with his club side last week and is to undergo surgery.

Tuipulotu, tipped as a candidate to feature for the British & Irish Lions later this year, is expected to return before the end of the season.

Scottish Rugby confirmed on its website on Monday that Rory Darge and Finn Russell will co-captain the side in this year's Six Nations.

Second row Scott Cummings is also likely to miss the tournament after fracturing his arm in the Warriors' 24-7 loss to Harlequins on Saturday.

Scotland have not yet called up any replacements, meaning they currently have a squad of 36 players.

Gregor Townsend's side begin their campaign against Italy at Murrayfield on 1 February.