And the in-demand defender’s arrival at Fratton Park isn't dependent on Matt Clarke leaving this summer.
The Blues have had a bid in excess of £600,000 accepted for the 21-year-old central defender.
And they are primed to beat off strong interest from Scottish giants Rangers, as well as Peterborough, to bring in the highly-regarded Latics talent.
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It's a move which shows Pompey mean business when it comes to their recruitment, and the challenge of bridging the gap from last season's near miss in the bid to reach the Championship.
Kenny Jackett is big fan of Edmundson, who really emerged at Boundary Park last season, making 54 of his 79 league appearances.
But Edmundson has now become the area of prime focus, after their offer usurped previous bids from Rangers.
Pompey’s offer is north of that figure, however, with personal terms to be agreed to see a switch completed.
Chief executive Mark Catlin has stated there is a contingency in place for any extra money coming into the club via player sales.
But the Blues are continuing with their efforts to bring in their targets, and are comfortable with the scenario of Clarke staying put for another season.
Edmundson is a right-footed defender who plays on the left side of a central partnership, meaning he would offer versatility to Jackett’s defensive options.
Paul Downing remains another strong summer option for Pompey with the move for the defender advancing.