Hibernian have bolstered their defence with the loan signings of Owen Bevan and Nectarios Triantis.
Both centre-backs are 20, with Bevan arriving from Bournemouth, while Sunderland's Triantis is reunited with head coach Nick Montgomery.
The Australian won last year's A-League title under Montgomery at Central Coast Mariners.
"I signed him for the Mariners and gave him his A-League debut as I saw huge potential in him," said Montgomery.
"He was a mainstay in our Championship winning team before joining Sunderland in the summer. Although he might not have played much, when he has featured, he's performed well.