Kenny Jackett has declared his hunt for central defenders is over.
Sean Raggett has signed on a season-long loan from Norwich to bolster the Blues’ defensive ranks.
They both will challenge Christian Burgess for a first-team spot, while promising Matt Casey is in the wings.
Meanwhile, former regular choice Jack Whatmough is out until February through injury.
And Pompey’s boss admits he is now fully stocked for centre-halves.
He said: ‘Looking at the centre-half department, we have added Raggett and Downing to Burgess, although losing Matt Clarke can be a big thing.
‘So we’ve got those three and Matt Casey. I am very confident of those going into the season.
‘It’s finished now, we have those four guys and I’m very pleased with the additions.
‘That should see us through in that particular position.’