Pompey are set to complete a triple attacking swoop ahead of Bournemouth.
Striker John Akinde is due to sign for the Blues today after leaving Crawley.
And he is expected to be joined by the double loan arrivals of Patrick Agyemang and Therry Racon.
Akinde trained with Pompey yesterday and is a free agent after leaving their League One rivals.
The 23-year-old has also spent time at Bristol City and had a number of spells on loan at lower-league sides.
Agyemang is due to join his new team-mates today from Stevenage with the emergency loan window opening.
Racon linked up with Pompey yesterday and will sign on loan from Millwall.
And Hayes & Yeading’s Alex N’Diaye is training with the side again after a trial last week.
Whittingham was keeping his cards close to his chest on Agyemang and Akinde but spoke of the boost Racon will provide.
He also refused to rule out a move for Svetoslav Todorov, although Pompey’s squad is at is 20-man capacity.
Whittingham said: ‘We tried to do Therry before deadline day but unfortunately it couldn’t be done.
‘So we had to look to the loan sign side of things.
‘Therry can play in a number of positions and is decent on the ball, so you need to get him on it as often as you can.
‘Alex trained yesterday. He’s a decent kid who wants to work on his fitness.
‘We’re up to 20 but it doesn’t rule (Todorov) out at the moment.
‘We have scope with month-to-month loans.
‘So if something does come to mind it can still go ahead.’