Brazilian defender linked with a return to Stamford Bridge.
Forward becomes Arsenal's third capture of the summer.
England skipper will retire from international duty after Russia 2018.
Hart could join Serie A side on season-long loan, while team-mate Samir Nasri could also be on his way.
After a quiet summer at the Emirates, Arsenal set for double swoop.
New Belgium coach hopes former striker can help realise the attacking potential within underachieving squad.
More money and more places guaranted for big four leagues as Champions League undergoes overhaul.
Return to Camp Nou for Pep Guardiola as Manchester City draw Barcelona.
England number one not on Everton's radar, says Koeman.
Arsene Wenger can offer guarantee of Champions League football to striker.