Ibrox side Glasgow Rangers defender Danny Wilson was a key player last season.
Firmino was impressive during the second half of Liverpool's campaign last season.
Southampton's Cedric and Jose Fonte both started for Portugal as they won Euro 2016.
The Arsenal defender has become Newcastle's fifth signing of the summer.
Nir Bitton has been linked with a move away from Celtic to Espanyol.
Premier League trio Tottenham Hotspur, West Bromwich Albion and Crystal Palace have all been linked with moves for Franco Vazquez of late.
The Sheffield Wednesday manager has also criticised Dimitri Payet’s tackle on Cristiano Ronaldo during the Euro 2016 final between Portugal and France.
Pelle looks set for a move to China, and no forward seems to be heading to St Mary's to replace him as of yet.
Nottingham Forest are said to be in competition with Rotherham United and Sheffield United for Brighton & Hove Albion's Jake Forster-Caskey.
Johnson, who was linked with moves to Old Firm pair Celtic and Rangers last month, is a reported target for QPR.