But Josh Adams and Steff Evans have stepped in impressively and caught the eye in Wales' strong start to the Championship.
Click here for the 2018 NatWest 6 Nations complete fixture list
That has meant that Cuthbert, included in Wales squad for this year's Championship, has not been able to add to his 47 caps for his country.
The 27-year-old suffered the knee injury in the Cardiff Blues final training session ahead of their Guinness PRO14 fixture against the Toyota Cheetahs last weekend.
Wales Squad Update: Alex Cuthbert released from Wales squad after suffering knee injury in Cardiff Blues' final training session ahead of their Guinness PRO14 fixture against Toyota Cheetahs last weekend.
- Welsh Rugby Union ? (@WelshRugbyUnion) February 13, 2018
But while Cuthbert is now out of the rest of the Championship, Warren Gatland will be pleased with the return to form and fitness of North who made a real impression off the bench at Twickenham.
A statement from Wales Rugby Union read: "Following subsequent scans and review with his Orthopaedic consultant, Alex will undergo surgery with a 4-6 week return to play time frame.
"With this in mind Alex will remain at the Blues for his medical management and will be released from the Wales national squad."
Want to know more about Wales in the NatWest 6 Nations?
Wales' third NatWest 6 Nations fixture of 2018 sees them take on Ireland on Saturday 24th February, 2:15pm at Aviva Stadium.
What are Wales' remaining 2018 NatWest 6 Nations fixtures?
Ireland v Wales, Sat 24 Feb 2018, 2:15pm
Wales v Italy, Sun 11 Mar 2018, 3:00pm
Wales v France, Sat 17 Mar 2018, 5:00pm
