Now the Giants' playing list is stocked with four previous No.1 draft selections and the Giants are set to welcome another wave of talent next month, including highly-rated academy duo Will Setterfield and Harry Perryman, after allowing nine players to move elsewhere.

Eleventh-hour signing Deledio (2004 draft) joins fellow top draftees Tom Scully (2009), Jonathon Patton (2011) and Lachie Whitfield (2012) for the price of a future first and third-round pick.

The Giants secured that first-round pick from Carlton just moments before making the Deledio trade official, along with selections 45 and 58 next month in exchange for key defender Caleb Marchbank and small forward Jarrod Pickett.

On a frantic final day of trading for GWS, Will Hoskin-Elliott went to Collingwood for a future second-round selection, Rhys Palmer went to Carlton for pick 135, James Stewart was traded for next month's 77th selection and Pat McKenna went to Melbourne.

GWS also offloaded picks 51 and 69 to the Demons as part of that exchange and received selections 57 and 59 in return.

But it was the last-minute Deledio deal that was the shrewdest piece of business done by head of football Wayne Campbell.

It is understood Deledio had long been on the GWS radar, but any hopes of a deal last week looked forlorn after the 29-year-old nominated Geelong as his preferred destination.

When the Cats move fell through, the Giants stepped in, gave him a tour of their western Sydney headquarters on Tuesday and agreed an in-principle deal with the Tigers on Wednesday.

"The club's had a fantastic ability to call on players in the second half of their careers, I suppose with the guys who have been well documented, and then go on to play as good a footy as they've ever played," Campbell said.

"That's certainly the aim for Brett. He gets another lease of life. We're really excited to have him."

The Giants were forced to cut their roster after the AFL decreed earlier this season that they would only be allowed a primary list of 40 players in 2017.

The expansion club will also be operating on a reduced salary as it is gradually brought into line with the rest of the competition.

"We've only been informed of that over the last 12 months, so we've probably had to cut a bit quicker than what we thought and that's probably resulted in those boys going for other opportunities at other clubs," Campbell said.

"We're fairly comfortable with the position we're in at the moment."

Meanwhile, the Swans will head into next month's draft with a top-10 draft pick for the first time since 2009.

Sydney head of football Tom Harley rounded out the trade period by swapping a handful of selections with GWS and then Port Adelaide, receiving picks No.9, 19 and 49 from the Power in exchange for 14, 17 and 31.

"Now we get to work with our recruiting department to make sure that we bring in the best young talent possible," Harley said.

The Swans shipped out two players during the trade period, Tom Mitchell making his highly-anticipated move to Hawthorn and ruckman Toby Nankervis heading to Richmond.