have spoken to about a loan for , with a potential obligation to buy.
The London club would prefer an outright sale, as they attempt to offload a number of squad players ahead of transfer deadline day in eight days' time.
With also considering Jackson, any move could have a knock-on effect on multiple other transfers.
Chelsea themselves are understood to be open to a versatile attacker should they complete enough outgoings, with an option that has been broached.
Atletico securing Jackson could meanwhile smooth 's departure - potentially to or even - in what is already a protracted saga.
If Jackson is to go, however, Villa is currently seen as more likely due to the expectation it would be a permanent move.
Atletico are understood to have approached Chelsea about a number of differently structured loans for the 25-year-old Senegalese attacker.