And Wenger's spending will not stop there as they have agreed a season-long loan deal for Palermo's Italian international keeper Emiliano Viviano, 27.
(read more after the cut)
Mirror Sport understands that Wojciech Szczesny will keep his place as No1 and Viviano is seen as top quality competition, back-up and strength in depth as he is a keeper capable of competing to be first choice.
Wenger is prepared to complete a deal for Ba despite his medical history but Chelsea have been reluctant to sell to a direct rival even though they are ready to offload him because they have a surplus of strikers.
Wenger tried to sign Ba in January but hesitated in January and allowed Chelsea to nip in and get him for £7m.
The Arsenal boss also tried to sign Ozil before he moved to Madrid and, while the size of the deal is a shock because of Wenger's reputation in transfer market, the signing shouldn't be.
Arsenal can see Ozil play in the middle with Santi Cazorla, who was always considered a wide player before moving to the Emirates, switching out left again.
But there is also talk of one more big deal at Arsenal. On top of all the others. Watch out as they have been tracking Angel Di Maria and Julian Draxler. Argentinian winger Di Maria has been on their radar for the past fortnight.