The goalkeeper will this afternoon undergo a scan on the injury which forced him off at half-time on his loan debut at Southend on Saturday.
However, Kenny Jackett has confirmed it’s the same area of the leg which Bass fractured at the start of January in a training ground collision.
Yet ahead of learning the full extent of the setback, there are legitimate concerns the keeper may have suffered the same injury.
While Southend manager Mark Molesley today claimed Bass’ season could now be over.
Pompey’s boss told The News: ‘Alex Bass has come back from Southend and is getting a scan this afternoon, so we’ll see the extent of his injury.
‘It’s the same foot which he’s had the problems with, but we don’t know any more than that.
‘It wasn’t one particular incident in the game, it just happened on landing, with nobody near him.
‘Although he carried on for the rest of the half, he felt enough to need to come off. We hope that things are not too bad.
‘A scan and an X-Ray this afternoon will give us more information.’
Meanwhile, Tom Naylor (back) and Ellis Harrison (knee) have been given the all-clear after receiving knocks in the 1-1 draw with Gillingham.
They are now expected to start Tuesday night’s trip to managerless Doncaster.
However, James Bolton today failed a fitness test on his ankle, meaning Haji Mnoga is pencilled in to retain his place.
Jackett added: ‘Naylor got a knock on the back, Harrison on his knee, they will be fit.
‘James Bolton is ruled out. He had a fitness test before training this morning, but he still wasn’t right.
‘We don’t think he’s too far away, another few days and every chance he will be fine for the weekend.’
A message from the Editor, Mark Waldron
The News has launched a new subscription offer which gives you unlimited access to all of our Pompey coverage, starting at less than £1 a week.
You can subscribe here to get the latest news and transfer updates from Fratton Park - and to support our local team of expert Pompey writers.