Pompey have ruled out any possible loan return for George Thorne and Scott Allan.
The Blues currently have two slots free in their 18-man squad, one of which has already been allocated for a new striker.
But Michael Appleton has admitted out-of-favour West Brom midfielders Thorne and Allan are out of his budget.
The pair made massive impacts on loan from the Baggies last season, with Allan, in particular, emerging as a key performer towards the end of his stint.
Since heading back to their parent club, however, they have made just one first-team appearance between them.
Thorne featured in a Capital One Cup success at Yeovil, playing the entire 90 minutes, while Allan has not played a single match.
The Fratton faithful would love to see them back in a Pompey shirt and so would Appleton.
But he concedes finances dictate he cannot offer them a loan route back to the south coast.
Appleton said: ‘Thorne and Scott would not be able to come here with our financial circumstances, absolutely no chance.
‘I remember in the summer I was interested in Chris Wood but, in the end, from a financial point of view, that was never going to happen, either.
‘Don’t get me wrong, with the budget I thought I was getting back in May he (Wood) would have been a very easy one to do.
‘But they aren’t going to happen now.’
Allan made 15 appearances for Pompey last season, scoring one goal.
Meanwhile, England under-19 Thorne enjoyed two spells at Fratton Park, featuring 13 times.