Frenchman Traore joins Pompey on a one-year loan deal following the conversion of Thomas' signing from a loan to a permanent signing.

The arrival of fellow Frenchman Mikael Silvestre's surprise £750,000 move to Emirates Stadium from Manchester United has given Arsenal manager Arsene Wenger the opportunity to send out the highly-rated 18-year-old to Fratton Park for more first-team experience.

Pompey will pay Charlton Athletic an undisclosed fee if 25-year-old Thomas, who joined last week and made his debut as a substitute in the 4-0 Barclays Premier League defeat at Chelsea, makes a specified number of appearances.

The South Coast club have made the change to Thomas' terms to free up more space for extra loan transfers to fit in with the Premier League's maximum of four per season per club, and thereby allowing for Traore's arrival.

With Ben Sahar already on a six-month stay  from Chelsea, Portsmouth had filled their quota of temporary transfers. However they now have space for one more - although that cannot be Chelsea winger Shaun Wright-Phillips as Barclays Premier League clubs are prohibited from borrowing more than one player from each team.

Chief executive Peter Storrie said: "It is a simple conversion from a loan deal to a permanent contract for a year. It frees up a loan space for us.

"Jerome could have been recalled by Charlton in January under the terms of his loan, but that's no longer a factor now."