The Sydney Swans, one of the more active clubs during trade week, were delighted to have snared untried Irishman Tommy Walsh from the Saints.
The Swans secured the strapping Walsh, who'd been on the Saints' rookie list for the past two seasons, for selections 35 and 68 at next month's AFL national draft.
The deal was only finalised 15 minutes before the close of business at 2pm AEDT on Monday.
Sydney also acquired Mitch Morton from Richmond for pick 79 and 22-year-old Tony Armstrong from the Adelaide Crows along with two draft selections in exchange for third-year forward Lewis Johnston.
Swans coach John Longmire believes Walsh, who is yet to play an AFL match, has plenty to offer.
"He's 194cm, he's 97kgs, he's a competitor and we thought that at either end of the ground he can play a role for us," Longmire said.
"Obviously when Lewis Johnston went out, another key position player coming in was a real priority for us."
The Saints said they were disappointed to lose Walsh who was keen to make the move to Sydney.
"The club reluctantly engaged in discussions with the Sydney Swans on the last day of trade week when it was clear that Tommy wouldn’t be returning to the Saints," said St Kilda's list manager Ameet Bains.
"The club, and no doubt Saints supporters, are disappointed but every effort was made to convince Tommy to stick around."
Longmire said Armstrong has a role to play as a ball-carrier while Morton is a proven goal kicker.
"Anyone who can kick 41 goals is a year has got some talent," said Longmire.
"Hopefully he can reproduce that."
"He's only 24, he's still only young so hopefully he can get back to his best."
"To be able to get some quality players in our club plus also keeping picks 43 and 61, we're pleased."