Journalist Tom Barclay believes Southampton have suffered a "massive blow" after Jack Stephens was ruled out of action for up to 12 weeks.
Why will Stephens be unavailable?
Stephens was forced off with a first half injury during Southampton's goalless draw with reigning Premier League champions Manchester City at the weekend.
Saints boss Ralph Hasenhuttl has since confirmed that Stephens sustained a tendon problem in his knee and will be kept on the sidelines for between 10 and 12 weeks.
It comes as a huge loss to the south-coast club as Stephens had played every minute of the campaign ahead of being substituted at the Etihad Stadium.
The central defender also played a key role in Saints keeping three clean sheets as Hasenhuttl's side got their season off to a positive start despite seeing key players such as Danny Ings and Jannik Vestergaard depart for Aston Villa and Leicester City respectively during the summer transfer window.
What has Tom Barclay said about Stephens' injury?
Barclay admits Stephens' spell on the sidelines will have a negative impact on Southampton.
Stephens has become a vital member of Saints' backline in recent seasons, with him making 139 appearances for the club.
Barclay believes the injury - along with its severity - is cruel on Stephens and his employers.
The journalist told GMS: "It's a massive blow because Jack Stephens has been at Southampton for a long time and always been a very dependable player.
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"Stephens came off after 37 minutes because of a problem with his tendon in his knee and he's out for 10 to 12 weeks.
"It's a big blow for Southampton and it's a really big blow for Stephens because it felt like he was forcing his way back in."
Who is likely to come into Saints' backline in Stephens' absence?
Like Stephens, Mohammed Salisu has started all of Southampton's Premier League fixtures so far this season, so it is now looking like a case of questioning who will partner him in the heart of the defence.
Poland international Jan Bednarek has made four appearances since the new campaign got underway last month, but the stalemate with Manchester City has been the 25-year-old's only start.
Stephens' injury could present an opportunity for Lyanco, who opted to swap Torino for Southampton despite interest from Watford and Italian side Udinese during the summer transfer window.
The Brazilian, 24, has yet to feature in the Premier League but made his Saints debut in the League Cup third round clash with Sheffield United earlier this week.