The Oman stopper enjoyed an excellent year on loan at the DW Stadium last term but Latics manager Roberto Martinez had taken his time trying to sort out a permanent move.
However, it is understood a transfer - said to be for a fee in the region of £4million - is likely to be concluded within the next 24 hours.
It will represent a good move for all parties, given Al Habsi had little chance of ousting Jussi Jaaskelainen at the Reebok Stadium.
"We could easily have kept him but I have to be fair to Ali," said manager Owen Coyle.
"It is good business. If that is concluded, we will wish him well.
"He did well at Wigan last year and they have tried to secure his services."