Portsmouth head coach John Mousinho already knew that Saturday's 2-2 draw at home to Blackburn Rovers was two points dropped rather than one gained. Now, according to BBC Radio Solent analyst Andrew Moon, the damage at the back looks considerably worse than a frustrating scoreline suggests.

Arthur ruled out until at least Christmas

The most serious blow is to Benji Arthur, who has been diagnosed with a stress fracture in his back. The centre-back is unlikely to feature again before Christmas, a blow that removes what Moon describes as one of Portsmouth's best two defenders at exactly the wrong moment. Stress fractures of that nature typically carry recovery timelines of three to four months, and Pompey supporters will be well aware how thin that leaves options at the heart of defence.

Conor Shaughnessy compounded the problem by going off against Blackburn holding his groin. Moon notes that even if the Irishman's injury proves minor, the incident only underlines that his minutes will need careful management. That has been achievable during what has been a relatively quiet opening to the campaign, but the schedule is about to become considerably more demanding.

Two conceded, two dropped

The defensive frailties were visible against Blackburn long before the full extent of the injury news became clear. Portsmouth had 20 shots across the ninety minutes, enough in most Championship matches to take all three points, yet a combination of committed visiting defending and some misfortune restricted them to two goals. The two they conceded at the other end were, by Moon's assessment, poor ones to give away, with goalkeeper Daniel Bielica sharing rather than shouldering the blame.

That is not an unusual situation in the second tier. Winning Championship matches when you concede twice is genuinely hard, regardless of how many chances you create going forward. Mousinho will know that better than most.

Fixture pile-up looms

The timing is awkward. Portsmouth now enter what Moon characterises as two extremely busy months, and the squad depth at centre-back that felt manageable a few weeks ago now looks stretched. The loss of Arthur for an extended period and the uncertainty over Shaughnessy's availability mean Mousinho must find either solutions from within the squad or explore the market, with the January transfer window still some way off.

This is the sort of problem that tests a manager's planning as much as his tactics. Whether Portsmouth have the necessary cover already on the books, or whether they will have to be creative in how they line up defensively, remains to be seen. Mousinho has spoken previously about building a squad capable of coping with absences, but losing two of your most reliable centre-backs in the same afternoon is a scenario that would test any club at this level.

Early season picture

Portsmouth's Championship campaign has been described, including on this site, as broadly acceptable without yet convincing anyone that the side is ready to push for the automatic promotion places. The defensive injury situation threatens to make an already demanding autumn considerably more complicated. Saturday's draw keeps them on the board but leaves questions unanswered about how they cope when their strongest defensive partnership is unavailable for a sustained period.

Mousinho and his staff will be working through those questions this week. The answers, or the lack of them, will tell supporters a great deal about where this Portsmouth side is genuinely headed.

Frequently asked

How long is Benji Arthur out for Portsmouth?
According to BBC Radio Solent, Arthur has suffered a stress fracture in his back and is unlikely to play again before Christmas.
What is Conor Shaughnessy's injury?
Shaughnessy went off against Blackburn Rovers holding his groin. The severity is not yet confirmed, but there are concerns his minutes will need to be carefully managed even if the injury is minor.
How are Portsmouth doing in the Championship this season?
Portsmouth picked up a 2-2 draw at home to Blackburn in their latest Championship match, a result that felt like two points dropped given they had 20 shots on the day.