Flanker CJ Stander is in a fight to be fit before the end of Ireland's Guinness Six Nations campaign due to suspected facial fractures.

Ireland expect Stander to be sidelined "for up to four weeks" following the nasty-looking facial injury he sustained in Saturday's 32-20 home loss to England.

Lock Devin Toner, wing Keith Earls and centre Garry Ringrose are all fitness doubts for Saturday's trip to face Scotland at Murrayfield, the Irish Rugby Football Union (IRFU) confirmed in a statement.

British and Irish Lions star Stander will hope he is able to return in time for Ireland's final two Six Nations matches, against France and Wales.

"CJ Stander has a facial injury that could rule him out for up to four weeks," read the IRFU statement.

"Keith Earls suffered a hip pointer injury and will be managed across the early part of the week.

"Devin Toner aggravated an ankle injury and Garry Ringrose reported some hamstring tightness. Both will be further assessed by the medical team over the next 24 hours.

"Andrew Conway presented with some calf tightness following training last Thursday and will rehab in Munster this week."

Stander's absence is a blow to head coach Joe Schmidt, with the South Africa-born back-rower proving a physical mainstay across 29 Ireland caps since his 2016 debut.

Stander's brother-in-law Ryk Neethling tweeted on Saturday night "proud of CJ Stander playing 62mins with two fractures in his cheek and eye socket", though Ireland are yet to confirm the full extent of the injuries.

A four-week lay-off could see Stander return for the Sunday, March 10 home clash with France, with the final clash in Wales on March 16 another likely target.

Leinster lock Toner's injury concern could dent Ireland's already depleted second-row stocks still further.

British and Irish Lions lock Iain Henderson is sidelined with a finger complaint and in-form Munster star Tadhg Beirne a knee issue.

Any further lock injuries could severely test Ireland's tight-five depth.

Ireland have not yet called a replacement into their squad however, hinting that they expect the 32-year-old to recover in time to face Scotland this weekend.

Ulster's versatile back Will Addison could slot into midfield should Ringrose not shake off his hamstring worry, while Schmidt will still ponder whether to run Robbie Henshaw again at full-back.