Pompey have reached an agreement with Dave Kitson over the termination of his contract.
The 32-year-old striker has signed a compromise agreement over money outstanding for the final year of his contract.
Blues administrator Trevor Birch said: “I’d like to thank Dave and his agent for the stance they’ve taken to give Portsmouth Football Club the best possible chance of survival.
“We thank Dave for his service to the club and wish him every success for the future.”
Kitson made 72 appearances for Pompey after arriving from Stoke in August 2010, making his debut in a goalless draw with Ipswich at Fratton Park.
He scored a total of 12 goals for the Blues, including a brace in a 6-1 home thrashing of Leicester.