Midfielder Lawrence has reached a compromise agreement with Pompey's administrators, paving the way for former owner Balram Chainrai's company Portpin to buy back the stricken south-coast club.
Administrator Trevor Birch had set a deadline of August 10 for every senior player to be off the wage bill, otherwise he would have to close Pompey down.
"We have negotiated a compromise agreement with Liam Lawrence, who will leave the club when the paperwork is finalised later (on Friday)," said Birch.
"I'd like to thank Liam for his support and all of the other players for putting the club's interest ahead of their own. They have all had to make very difficult decisions and been placed in an impossible position which wasn't of their making."
- Balram Chainrai