Luke Varney has been ruled out of Saturday’s Coventry City clash.
Pompey’s top scorer remains sidelined with a hamstring injury.
He failed a late fitness test hours before last weekend’s Leicester fixture.
But the grade one tear has not healed sufficiently for a return against the Sky Blues.
Now Michael Appleton is pencilling in Varney for the December 10 trip to Burnley.
He said: ‘Luke’s hamstring is not too bad, he is progressing well.
‘But I think this weekend is a little bit too quick for him.
‘It’s a grade one hamstring tear and one of those where he could be out for a couple of weeks
‘We’ve already had a week, so we are now looking at Burnley.
‘Luke had a fitness test before the Leicester game, but it would have been a risk playing him and could have kept him out longer.
‘It was the right decision.
‘Luke is an important player and we don’t want any set-backs.’
In addition, Liam Lawrence will also miss the Coventry clash.
The club captain has been out since damaging ankle ligaments a month ago.
He has returned to the training pitch this week.
However, the midfielder has yet to take part in ball work with his team-mates.
And Appleton does not believe he will be ready for the visit of the Sky Blues.
The Blues boss added: ‘This weekend will also be too soon for Liam.
‘He has come back onto the training field, which is encouraging, but has yet to do any ball work with the players.
‘That may change tomorrow.
‘But he won’t be ready to feature against Coventry so again we’re looking at next week.’