The midfielder's month-to-month contract was due to expire after the game but he has confirmed he has already become the latest player to leave Fratton Park.
He said via Twitter: "4 those that want 2 see the back of me ur wishes have come true.
"4 those who have showed me support thank u + appreciate those comments. I have enjoyed playing for Portsmouth and wish things were different."
Caretaker boss Guy Whittingham, who lost half of his first team earlier this month as the club continue to cut costs, could hand on-loan youngster Frankie Sutherland a full debut in Russell's place.
Sutherland came on as a substitute as one of seven debutants as Pompey crashed 3-1 to bottom side Hartlepool on Saturday, their 15th game without a win.
Defender Sam Sodje, an unused sub at the weekend, could make his first appearance against the side he left in May.