Last week, it was claimed that the Premier League champions were 'growing increasingly confident' of completing a deal for the 23-year-old, who has rejected the chance to sign a new contract at the Emirates Stadium.
The midfielder scored twice and registered seven assists in 29 Premier League appearances for Arsenal during the 2016-17 campaign, but he struggled to hold down a regular position in the team.
He has started all three of Arsenal's Premier League fixtures this season, however, including the 4-0 defeat at Liverpool on Sunday afternoon.
According to Sky Sports News, Arsenal have agreed to sell the England international to their London rivals for £35m, and a medical could be carried out at England's training base.
Oxlade-Chamberlain has scored 20 times in 197 appearances for Arsenal following a 2011 move from Southampton.