James Vaughan’s frustrating Fratton Park residency has suffered another setback.
But Kenny Jackett believes the loanee striker can still make a Pompey impact.
The 30-year-old sustained a back spasm during a substitute appearance in Tuesday night's 3-2 victory at Walsall.
A knee to the back caused the much-travelled forward to limp noticeably during a 14-minute cameo, yet he saw out the final whistle.
Jackett revealed a back issue had troubled Vaughan even before his Bescot Stadium injury.
The former Everton man has yet to start a Pompey match since his January transfer-window switch, appearing from the bench seven times.
Now a back injury is hindering his starting chances.
Pompey’s boss said: ‘James has a bad back, we will see if he can make it.
‘I wouldn’t say he is definitely out, but he is an injury doubt for Scunthorpe after it flared up at Walsall.
‘He was feeling it and holding it towards the end of the game, I nearly had to sub the sub.
‘A knee in the back caused a spasm and you could see him limping on the pitch.
‘It’s something he’s had for a week for two, he’s felt it once or twice, so we’ll have to see how he does.
‘James is a good player and he gives us good competition. He’s not had the chance from the start of a match yet, though.
‘But there are games remaining and we’ll be looking to all of our players to help us through and finish as highly as we possibly can.’
Should Vaughan miss out against Scunthorpe, that will open the door for Lloyd Isgrove to sit on Pompey’s bench.
The winger, captured on loan from Barnsley, has still to feature for the Blues, while made just a single squad to date.
Definitely missing are Bryn Morris (knee) and Andy Cannon (thigh), now pencilled in to return within the next fortnight.
The January transfer window saw six new faces at Fratton Park, with Vaughan, Isgrove, Morris and Cannon among them.
The remaining two, Omar Bogle and Viv Solomon-Otabor, are expected to start against Scunthorpe tomorrow.
The loan pair scored upon recalls to Jackett’s side in the week, that Walsall triumph representing Pompey’s first League One away win of 2019.