Pompey have been unable to register new players since October after concerns over unpaid football debts - most notably concerning fees owed to Udinese for the departed Sulley Muntari - but now have just under a week before the January window shuts to bolster their relegation-threatened squad.
Former Chelsea boss Avram Grant, who took the top job following Paul Hart's sacking two months ago, is sure to have his own targets but the first order of business is a new loan deal for O'Hara.
The 23-year-old spent the first half of the season at Fratton Park but despite an agreement being in place between Spurs and Portsmouth to extend the deal until the end of the campaign, he was forced to return to London due to the embargo.
Now chief executive Peter Storrie has revealed the club are hoping to get O'Hara back as soon as possible, as well as up to three more new faces.
Recruitment is unlikely to be straightforward, with the club's financial struggles meaning they are restricted to short-term deals and free transfers, but additions are almost certain.
Storrie told BBC Radio Five Live: "(The announcement) is major news, it means we can can do something between now and the end of the window.
"It's a boost for Avram, a boost for the team and the supporters.
"We're looking to bring in two or three players, ideally four if we can and that would include bringing Jamie O'Hara back, which is our first priority now.
"If we can bring in three or four we believe we have a chance of staying up."
The Premier League's official statement in lifting the registration embargo read: "The board of the Premier League has today lifted the player registration embargo on Portsmouth Football Club under the conditions that they are limited to signing players on loan or who are available on a free transfer.
"The board has taken this action as Portsmouth FC has no outstanding debts to football clubs as of this date."
Storrie, though, was unable to offer cast-iron guarantees that the players would be paid on time this month, after their December wages were received only after several delays.
He said: "As far as I understand, and I can only pass on what I'm told by the owners, the finances are under control. I don't deal with the finance side of the business so I can't say one way or another."