If it’s bad news over the League One title winner it’s a significant blow, following his reassuring return from a five-month calf lay-off.
There are options at the back for John Mousinho, but the Pompey boss does have the option of moving into the free agent market to bolster his back line.
The Blues have left one space open in their 25-man squad to do just that, something the recruitment did last year when impacted by midfield issues.
Lee Evans arrived to bolster that department back then - here’s a list of 12 central defenders who could do likewise this time.
5. Kenneth Omeruo
Former Chelsea man saw his contract cancelled by Turkish outfit Kasimpasa last month. The 6ft 1in man signed for Chelsea in 2012 and then had a loan spell in the Championship with Middlesbrough, but has been hampered by injuries in more recent times. | Getty Images
6. Erik Pieters
Vastly-experienced Dutchman who played at the highest level with Stoke and was operating in the Championship with West Brom last term. Signed a short-term deal with Luton at the end of last year, but the 36-year-old has left Kenilworth Road and is available. Photo: Catherine Ivill
7. James Tomkins
Now 35, but the former West Ham man played in the Premier League for Crystal Palace last season. Has been touted for a move to Millwall and made it clear he still thinks he has something offer, before he hangs up to boots. Photo: Alex Davidson
8. Jason Denayer
The former Lyon and Sunderland defender left Saudi Pro League side Al Fateh a couple of weeks ago and is looking for a new club. The 29-year-old can play in the middle, right back or as defensive midfielder. Picked up Premier League experience with the Black Cats in the 2016-17 campaign. Been earning big bucks in the Middle East football backwater, but has lost his top-level status as a result. Photo: ROMAIN PERROCHEAU