Lee Brown is set to be sidelined for around six weeks after injuring his Achilles.
The left-back limped off the pitch during the first half of last Tuesday’s 3-3 draw with Coventry at Fratton Park.
But Kenny Jackett believes that academy graduate Brandon Haunstrup has all the attributes needed to fill the gap.
The Blues boss said: “Lee’s got an Achilles injury and we’re estimating that the total time he’ll be out will be around six weeks.
“Our focus now is on Brandon. He’s 22 and it’s time for him to do well – he’s certainly capable of doing that.
"Lee’s got an Achilles injury and we’re estimating that the total time he’ll be out will be around six weeks."
“Bryn Morris still has a problem with his stomach injury and he’s as frustrated as anyone about how the season has started.
“Ryan Williams and Oli Hawkins should be training towards the back end of the week, so neither are expected to feature on Wednesday or Saturday.”
Jackett also confirmed that he is running the rule over James Meredith, who was most recently at Millwall.
He said: “James has had a few days training with us and that will continue. He’s an experienced player and Brandon is currently our only naturally left-footed player.”