Portsmouth are waiting to learn the extent of Luke Varney's knee injury after the striker was forced off against Burnley on Saturday.
Varney, who has only recently recovered from a hamstring problem, limped off in the 20th minute at Turf Moor following a challenge by Clarets goalkeeper Lee Grant.
Pompey will assess the extent of the knock this week in the hope he will be fit in time for Sunday's eagerly-anticipated South Coast derby against Southampton.
"It is not Luke's hamstring - he's got a bang to his knee," said Pompey boss Michael Appleton.
"As he lifted the ball over Grant he caught his knee so it is more of an impact injury.
"It's a little bit sore at the minute and a bit stiff. He's had a little bit of ice and we are hoping it will settle down and we will see how bad it is.
"Today we will have an idea of where we are with him, so we will have to reassess him after that."